DTC U1204:00 [PCM (SKYACTIV-D 2.2)]

DTC U1204:00	LIN communication system: fuel Injector No.4 information communication error with PCM
DETECTION CONDITION	• When any of the following conditions is met: ― With all the following conditions met, a communication error between fuel injector No.4 and the PCM occurs. • Battery positive voltage: 10.5—18.0 V • Fuel injector: DTCs P10C2:00, P10C3:00, P10C5:00, P10C6:00, P10C8:00, P10C9:00, P10CB:00, and P10CC:00 are not detected ― With all of the following conditions met, the PCM cannot identify fuel injector No.4 with the ignition switched ON (engine off or on). • Battery positive voltage: 10.5—18.0 V • Fuel injector: DTCs P10C2:00, P10C3:00, P10C5:00, P10C6:00, P10C8:00, P10C9:00, P10CB:00, and P10CC:00 are not detected Diagnostic support note • This is a continuous monitor (CCM). • The check engine light illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. • PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle. • FREEZE FRAME DATA/Snapshot data is available. • DTC is stored in the PCM memory.
FAIL-SAFE FUNCTION	• Not applicable
POSSIBLE CAUSE	• Short to power supply in wiring harness between the following terminals ― Fuel injector No.1 terminal D and PCM terminal 1T ― Fuel injector No.2 terminal D and PCM terminal 1V ― Fuel injector No.3 terminal D and PCM terminal 1P ― Fuel injector No.4 terminal D and PCM terminal 1U • Short to ground in wiring harness between the following terminals ― Fuel injector No.1 terminal D and PCM terminal 1T ― Fuel injector No.2 terminal D and PCM terminal 1V ― Fuel injector No.3 terminal D and PCM terminal 1P ― Fuel injector No.4 terminal D and PCM terminal 1U • Open circuit in wiring harness between fuel injector No.4 terminal D and PCM terminal 1U • Fuel injector No.4 connector or terminal malfunction • Fuel injector No.4 malfunction • PCM connector or terminal malfunction • PCM malfunction

DTC U1204:00

LIN communication system: fuel Injector No.4 information communication error with PCM

DETECTION CONDITION

• When any of the following conditions is met:

― With all the following conditions met, a communication error between fuel injector No.4 and the PCM occurs.

• Battery positive voltage: 10.5—18.0 V

• Fuel injector: DTCs P10C2:00, P10C3:00, P10C5:00, P10C6:00, P10C8:00, P10C9:00, P10CB:00, and P10CC:00 are not detected

― With all of the following conditions met, the PCM cannot identify fuel injector No.4 with the ignition switched ON (engine off or on).

• Battery positive voltage: 10.5—18.0 V

• Fuel injector: DTCs P10C2:00, P10C3:00, P10C5:00, P10C6:00, P10C8:00, P10C9:00, P10CB:00, and P10CC:00 are not detected

Diagnostic support note

• This is a continuous monitor (CCM).

• The check engine light illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.

• PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle.

• FREEZE FRAME DATA/Snapshot data is available.

• DTC is stored in the PCM memory.

FAIL-SAFE FUNCTION

• Not applicable

POSSIBLE CAUSE

• Short to power supply in wiring harness between the following terminals

― Fuel injector No.1 terminal D and PCM terminal 1T

― Fuel injector No.2 terminal D and PCM terminal 1V

― Fuel injector No.3 terminal D and PCM terminal 1P

― Fuel injector No.4 terminal D and PCM terminal 1U

• Short to ground in wiring harness between the following terminals

― Fuel injector No.1 terminal D and PCM terminal 1T

― Fuel injector No.2 terminal D and PCM terminal 1V

― Fuel injector No.3 terminal D and PCM terminal 1P

― Fuel injector No.4 terminal D and PCM terminal 1U

• Open circuit in wiring harness between fuel injector No.4 terminal D and PCM terminal 1U

• Fuel injector No.4 connector or terminal malfunction

• Fuel injector No.4 malfunction

• PCM connector or terminal malfunction

• PCM malfunction

Step	Inspection	Results	Action
1	RECORD VEHICLE STATUS WHEN DTC WAS DETECTED TO UTILIZE WITH REPEATABILITY VERIFICATION Note • Recording can be facilitated using the screen capture function of the PC. • Record the freeze frame data/snap shot data.	—	Go to the next step.
2	VERIFY OTHER RELATED DTCs • Switch the ignition OFF, and then switch it ON (engine off). • Display the DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-D 2.2)].) • Has any DTC other than U1204:00 been stored?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [PCM (SKYACTIV-D 2.2)].)
No	Go to the next step.
3	INSPECT FUEL INJECTOR NO.4 CONNECTOR CONDITION • Switch the ignition OFF. • Disconnect the fuel injector No.4 connector. • Inspect the connector engagement and connection condition, and inspect the terminals for damage, deformation, corrosion, or disconnection. • Is the connector normal?	Yes	Go to the next step.
No	Repair or replace the connector, then go to Step 15.
4	INSPECT PCM CONNECTOR CONDITION • Disconnect the PCM connector. • Inspect the connector engagement and connection condition, and inspect the terminals for damage, deformation, corrosion, or disconnection. • Is the connector normal?	Yes	Go to the next step.
No	Repair or replace the connector, then go to Step 15.
5	INSPECT FUEL INJECTOR NO.1 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY • Verify that the fuel injector No.1 connector and the PCM connector are disconnected. • Switch the ignition ON (engine off). Note • Another DTC may be stored by the PCM detecting an open circuit. • Measure the voltage at fuel injector No.1 terminal D (vehicle wiring harness side). • Is the voltage 0 V?	Yes	Go to the next step.
No	Refer to the wiring diagram and verify if there is a common connector between fuel injector No.1 terminal D and PCM terminal 1T. If there is a common connector: • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which is shorted to the power supply. Go to Step 15.
6	INSPECT FUEL INJECTOR NO.2 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY • Verify that the fuel injector No.2 connector and the PCM connector are disconnected. • Switch the ignition ON (engine off). Note • Another DTC may be stored by the PCM detecting an open circuit. • Measure the voltage at fuel injector No.2 terminal D (vehicle wiring harness side). • Is the voltage 0 V?	Yes	Go to the next step.
No	Refer to the wiring diagram and verify if there is a common connector between fuel injector No.2 terminal D and PCM terminal 1V. If there is a common connector: • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which is shorted to the power supply. Go to Step 15.
7	INSPECT FUEL INJECTOR NO.3 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY • Verify that the fuel injector No.3 connector and the PCM connector are disconnected. • Switch the ignition ON (engine off). Note • Another DTC may be stored by the PCM detecting an open circuit. • Measure the voltage at fuel injector No.3 terminal D (vehicle wiring harness side). • Is the voltage 0 V?	Yes	Go to the next step.
No	Refer to the wiring diagram and verify if there is a common connector between fuel injector No.3 terminal D and PCM terminal 1P. If there is a common connector: • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which is shorted to the power supply. Go to Step 15.
8	INSPECT FUEL INJECTOR NO.4 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY • Verify that the fuel injector No.4 connector and the PCM connector are disconnected. • Switch the ignition ON (engine off). Note • Another DTC may be stored by the PCM detecting an open circuit. • Measure the voltage at fuel injector No.4 terminal D (vehicle wiring harness side). • Is the voltage 0 V?	Yes	Go to the next step.
No	Refer to the wiring diagram and verify if there is a common connector between fuel injector No.4 terminal D and PCM terminal 1U. If there is a common connector: • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which is shorted to the power supply. Go to Step 15.
9	INSPECT FUEL INJECTOR CIRCUIT FOR SHORT TO GROUND • Verify that the fuel injector No.1 connector and the PCM connector are disconnected. • Inspect for continuity between fuel injector No.1 terminal D (vehicle wiring harness side) and ground. • Is there continuity?	Yes	Refer to the wiring diagram and verify if there is a common connector between fuel injector No.1 terminal D and PCM terminal 1T. If there is a common connector: • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which is shorted to ground. Go to Step 15.
No	Go to the next step.
10	INSPECT FUEL INJECTOR CIRCUIT FOR SHORT TO GROUND • Verify that the fuel injector No.2 connector and the PCM connector are disconnected. • Inspect for continuity between fuel injector No.2 terminal D (vehicle wiring harness side) and ground. • Is there continuity?	Yes	Refer to the wiring diagram and verify if there is a common connector between fuel injector No.2 terminal D and PCM terminal 1V. If there is a common connector: • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which is shorted to ground. Go to Step 15.
No	Go to the next step.
11	INSPECT FUEL INJECTOR CIRCUIT FOR SHORT TO GROUND • Verify that the fuel injector No.3 connector and the PCM connector are disconnected. • Inspect for continuity between fuel injector No.3 terminal D (vehicle wiring harness side) and ground. • Is there continuity?	Yes	Refer to the wiring diagram and verify if there is a common connector between fuel injector No.3 terminal D and PCM terminal 1P. If there is a common connector: • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which is shorted to ground. Go to Step 15.
No	Go to the next step.
12	INSPECT FUEL INJECTOR CIRCUIT FOR SHORT TO GROUND • Verify that the fuel injector No.4 connector and the PCM connector are disconnected. • Inspect for continuity between fuel injector No.4 terminal D (vehicle wiring harness side) and ground. • Is there continuity?	Yes	Refer to the wiring diagram and verify if there is a common connector between fuel injector No.4 terminal D and PCM terminal 1U. If there is a common connector: • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which is shorted to ground. Go to Step 15.
No	Go to the next step.
13	INSPECT FUEL INJECTOR NO.4 CIRCUIT FOR OPEN CIRCUIT • Verify that the fuel injector No.4 connector and the PCM connector are disconnected. • Inspect the wiring harness for continuity between fuel injector No.4 terminal D and PCM terminal 1U (vehicle wiring harness side). • Is there continuity?	Yes	Go to the next step.
No	Refer to the wiring diagram and verify if there is a common connector between fuel injector No.4 terminal D and PCM terminal 1U. If there is a common connector: • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location. • Repair or replace the malfunctioning location. If there is no common connector: • Repair or replace the wiring harness which has an open circuit. Go to Step 15.
14	INSPECT FUEL INJECTOR NO.4 • Inspect fuel injector No.4. (See FUEL INJECTOR INSPECTION [SKYACTIV-D 2.2].) • Is fuel injector No.1 normal?	Yes	Go to the next step.
No	Replace fuel injector No.4, then go to the next step. (See FUEL INJECTOR REMOVAL/INSTALLATION [SKYACTIV-D 2.2].)
15	VERIFY THAT REPAIRS HAVE BEEN COMPLETED • Reconnect all the disconnected connectors. • Refer to the [MEMORY CLEARING PROCEDURE] and clear the DTC. (See CLEARING DTC [PCM (SKYACTIV-D 2.2)].) • Switch the ignition ON (engine off) and leave for 10 s. • Display the DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-D 2.2)].) • Has DTC U1204:00 been recorded?	Yes	Repeat the inspection from Step 1. • If the malfunction recurs, replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [SKYACTIV-D 2.2].)
No	Go to the next step.
16	VERIFY OTHER DTCs • Has any other DTC or pending code been stored?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [PCM (SKYACTIV-D 2.2)].)
No	DTC troubleshooting completed.

Step

Inspection

Results

Action

RECORD VEHICLE STATUS WHEN DTC WAS DETECTED TO UTILIZE WITH REPEATABILITY VERIFICATION

Note

• Recording can be facilitated using the screen capture function of the PC.

• Record the freeze frame data/snap shot data.

—

Go to the next step.

VERIFY OTHER RELATED DTCs

• Switch the ignition OFF, and then switch it ON (engine off).

• Display the DTCs using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-D 2.2)].)

• Has any DTC other than U1204:00 been stored?

Yes

Repair the malfunctioning location according to the applicable DTC troubleshooting.

(See DTC TABLE [PCM (SKYACTIV-D 2.2)].)

Go to the next step.

INSPECT FUEL INJECTOR NO.4 CONNECTOR CONDITION

• Switch the ignition OFF.

• Disconnect the fuel injector No.4 connector.

• Inspect the connector engagement and connection condition, and inspect the terminals for damage, deformation, corrosion, or disconnection.

• Is the connector normal?

Yes

Go to the next step.

Repair or replace the connector, then go to Step 15.

INSPECT PCM CONNECTOR CONDITION

• Disconnect the PCM connector.

• Inspect the connector engagement and connection condition, and inspect the terminals for damage, deformation, corrosion, or disconnection.

• Is the connector normal?

Yes

Go to the next step.

Repair or replace the connector, then go to Step 15.

INSPECT FUEL INJECTOR NO.1 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY

• Verify that the fuel injector No.1 connector and the PCM connector are disconnected.

• Switch the ignition ON (engine off).

Note

• Another DTC may be stored by the PCM detecting an open circuit.

• Measure the voltage at fuel injector No.1 terminal D (vehicle wiring harness side).

• Is the voltage 0 V?

Yes

Go to the next step.

Refer to the wiring diagram and verify if there is a common connector between fuel injector No.1 terminal D and PCM terminal 1T.

If there is a common connector:

• Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location.

• Repair or replace the malfunctioning location.

If there is no common connector:

• Repair or replace the wiring harness which is shorted to the power supply.

Go to Step 15.

INSPECT FUEL INJECTOR NO.2 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY

• Verify that the fuel injector No.2 connector and the PCM connector are disconnected.

• Switch the ignition ON (engine off).

Note

• Another DTC may be stored by the PCM detecting an open circuit.

• Measure the voltage at fuel injector No.2 terminal D (vehicle wiring harness side).

• Is the voltage 0 V?

Yes

Go to the next step.

Refer to the wiring diagram and verify if there is a common connector between fuel injector No.2 terminal D and PCM terminal 1V.

If there is a common connector:

• Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location.

• Repair or replace the malfunctioning location.

If there is no common connector:

• Repair or replace the wiring harness which is shorted to the power supply.

Go to Step 15.

INSPECT FUEL INJECTOR NO.3 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY

• Verify that the fuel injector No.3 connector and the PCM connector are disconnected.

• Switch the ignition ON (engine off).

Note

• Another DTC may be stored by the PCM detecting an open circuit.

• Measure the voltage at fuel injector No.3 terminal D (vehicle wiring harness side).

• Is the voltage 0 V?

Yes

Go to the next step.

Refer to the wiring diagram and verify if there is a common connector between fuel injector No.3 terminal D and PCM terminal 1P.

If there is a common connector:

• Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location.

• Repair or replace the malfunctioning location.

If there is no common connector:

• Repair or replace the wiring harness which is shorted to the power supply.

Go to Step 15.

INSPECT FUEL INJECTOR NO.4 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY

• Verify that the fuel injector No.4 connector and the PCM connector are disconnected.

• Switch the ignition ON (engine off).

Note

• Another DTC may be stored by the PCM detecting an open circuit.

• Measure the voltage at fuel injector No.4 terminal D (vehicle wiring harness side).

• Is the voltage 0 V?

Yes

Go to the next step.

Refer to the wiring diagram and verify if there is a common connector between fuel injector No.4 terminal D and PCM terminal 1U.

If there is a common connector:

• Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location.

• Repair or replace the malfunctioning location.

If there is no common connector:

• Repair or replace the wiring harness which is shorted to the power supply.

Go to Step 15.

INSPECT FUEL INJECTOR CIRCUIT FOR SHORT TO GROUND

• Verify that the fuel injector No.1 connector and the PCM connector are disconnected.

• Inspect for continuity between fuel injector No.1 terminal D (vehicle wiring harness side) and ground.

• Is there continuity?

Yes

Refer to the wiring diagram and verify if there is a common connector between fuel injector No.1 terminal D and PCM terminal 1T.

If there is a common connector:

• Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.

• Repair or replace the malfunctioning location.

If there is no common connector:

• Repair or replace the wiring harness which is shorted to ground.

Go to Step 15.

Go to the next step.

INSPECT FUEL INJECTOR CIRCUIT FOR SHORT TO GROUND

• Verify that the fuel injector No.2 connector and the PCM connector are disconnected.

• Inspect for continuity between fuel injector No.2 terminal D (vehicle wiring harness side) and ground.

• Is there continuity?

Yes

Refer to the wiring diagram and verify if there is a common connector between fuel injector No.2 terminal D and PCM terminal 1V.

If there is a common connector:

• Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.

• Repair or replace the malfunctioning location.

If there is no common connector:

• Repair or replace the wiring harness which is shorted to ground.

Go to Step 15.

Go to the next step.

INSPECT FUEL INJECTOR CIRCUIT FOR SHORT TO GROUND

• Verify that the fuel injector No.3 connector and the PCM connector are disconnected.

• Inspect for continuity between fuel injector No.3 terminal D (vehicle wiring harness side) and ground.

• Is there continuity?

Yes

Refer to the wiring diagram and verify if there is a common connector between fuel injector No.3 terminal D and PCM terminal 1P.

If there is a common connector:

• Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.

• Repair or replace the malfunctioning location.

If there is no common connector:

• Repair or replace the wiring harness which is shorted to ground.

Go to Step 15.

Go to the next step.

INSPECT FUEL INJECTOR CIRCUIT FOR SHORT TO GROUND

• Verify that the fuel injector No.4 connector and the PCM connector are disconnected.

• Inspect for continuity between fuel injector No.4 terminal D (vehicle wiring harness side) and ground.

• Is there continuity?

Yes

Refer to the wiring diagram and verify if there is a common connector between fuel injector No.4 terminal D and PCM terminal 1U.

If there is a common connector:

• Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.

• Repair or replace the malfunctioning location.

If there is no common connector:

• Repair or replace the wiring harness which is shorted to ground.

Go to Step 15.

Go to the next step.

INSPECT FUEL INJECTOR NO.4 CIRCUIT FOR OPEN CIRCUIT

• Verify that the fuel injector No.4 connector and the PCM connector are disconnected.

• Inspect the wiring harness for continuity between fuel injector No.4 terminal D and PCM terminal 1U (vehicle wiring harness side).

• Is there continuity?

Yes

Go to the next step.

Refer to the wiring diagram and verify if there is a common connector between fuel injector No.4 terminal D and PCM terminal 1U.

If there is a common connector:

• Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.

• Repair or replace the malfunctioning location.

If there is no common connector:

• Repair or replace the wiring harness which has an open circuit.

Go to Step 15.

INSPECT FUEL INJECTOR NO.4

• Inspect fuel injector No.4.

(See FUEL INJECTOR INSPECTION [SKYACTIV-D 2.2].)

• Is fuel injector No.1 normal?

Yes

Go to the next step.

Replace fuel injector No.4, then go to the next step.

(See FUEL INJECTOR REMOVAL/INSTALLATION [SKYACTIV-D 2.2].)