DTC P1788, P1789[LA4AX-EL (CD4E)]

id050207807800

DTC P1788

3-2 timing/coast clutch solenoid (3-2 T/CCS) circuit malfunction (open circuit/short to power supply)

DTC P1789

3-2 timing/coast clutch solenoid (3-2 T/CCS) circuit malfunction (short to ground)
DETECTION CONDITION
•  Open or short circuit in circuit between 3-2 timing/coast clutch solenoid and PCM, or in 3-2 timing/coast clutch solenoid internal circuit
POSSIBLE CAUSE
•  3-2T/CCS malfunction.
•  Main relay and fuse malfunction.
•  Short to ground in wiring harness between main relay and ATX connector terminal D (transaxle case side).
•  Open circuit in wiring harness between main relay and ATX connector terminal D (transaxle case side).
•  Short to ground in wiring harness between ATX connector terminal I (wiring harness-side) and PCM terminal 20 (wiring harness-side).
•  Short to power supply in wiring harness between ATX connector terminal I (wiring harness-side) and PCM terminal 20 (wiring harness-side).
•  Open circuit in wiring harness between ATX connector terminal I (wiring harness-side) and PCM terminal /20 (wiring harness-side).
•  Damaged connector between 3-2T/CCS and PCM.
•  PCM malfunction.

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•  Has the FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service Information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
INSPECT ATX CONNECTOR FOR POOR CONNECTION
•  Turn the ignition switch to the LOCK position.
•  Inspect ATX connector connection.
•  Disconnect the ATX connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is the connection normal?
Yes
Go to the next step.
No
Repair or replace the connector and/or terminals, then go to Step 10.
4
INSPECT POWER SUPPLY CIRCUIT
•  Turn the ignition switch to the ON position (engine off).
•  Inspect voltage at ATX connector terminal D (wiring harness-side).
•  Is the voltage approx. 12 V?
Yes
Go to the next step.
No
Inspect the fuse, main relay and wiring harness, then go to Step 10.
5
INSPECT RESISTANCE
•  Turn the ignition switch to the LOCK position.
•  Inspect resistance between ATX terminal D and I (transaxle case side).
•  Is resistance within 3.75—5.92 ohms?
Yes
Go to the next step.
No
Replace the 3-2T/CCS, then go to Step 10.
6
INSPECT PCM CONNECTOR FOR POOR CONNECTION
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is the connection normal?
Yes
Go to the next step.
No
Repair or replace connector and/or terminals, then go to Step 10.
7
INSPECT 3-2T/CCS CIRCUIT FOR OPEN CIRCUIT
•  Inspect for continuity between PCM terminal 20 (wiring harness-side) and ATX connector terminal I (wiring harness-side).
•  Is there continuity between terminals?
Yes
Go to the next step.
No
Repair or replace the wiring harness, then go to Step 10.
8
INSPECT 3-2T/CCS CIRCUIT FOR SHORT TO GROUND
•  Turn the ignition switch to the LOCK position.
•  Inspect continuity between ATX connector terminal I (wiring harness-side) and body ground.
•  Is there continuity?
Yes
Repair or replace the wiring harness, then go to the Step 10.
No
Go to the next step.
9
INSPECT 3-2T/CCS CIRCUIT FOR SHORT TO POWER SUPPLY
•  Turn the ignition switch to the ON position (engine off).
•  Inspect voltage at ATX connector terminal I (wiring harness-side).
•  Is the voltage 0 V?
Yes
Go to the next step.
No
Repair or replace the wiring harness, then go to the next step.
10
VERIFY TROUBLESHOOTING OF DTC P1788 OR P1789 COMPLETED
•  Make sure to reconnect all the disconnected connectors.
•  Clear the DTC from memory using the M-MDS.
•  Perform the “After Repair Procedure”.
•  Are any DTCs present?
Yes
Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION[AJ (3.0L Duratec)].)
No
Go to the next step.
11
VERIFY DTCS
•  Are except DTC P1788 and P1789 output?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE[LA4AX-EL (CD4E)].)
No
DTC troubleshooting completed.