DTC P0231:00 [MZI-3.7 (PCM CONNECTOR (3 TYPES))]

id0102e4505300

DTC P0231:00

Fuel pump secondary circuit low
DETECTION CONDITION
•  The PCM monitors the fuel pump monitor circuit. The test fails if the PCM commands the fuel pump ON and B+ voltage is not detected on the FPM circuit.
POSSIBLE CAUSE
•  Open B+ circuit to the fuel pump relay terminal C
•  Open FP PWR circuit between the fuel pump relay terminal D and its connection to the PCM terminal 1H
•  Damaged fuel pump relay
•  PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•  Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record 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
CHECK PROBLEM IS CONTINUING
•  Perform the KOEO self-test.
•  Is the DTC P0231:00 present?
Yes
Go to the next step.
No
Go to Step 11.
4
CHECK FOR FUEL PUMP RELAY PRIMARY CIRCUIT PROBLEM ALSO PRESENT
•  Turn the ignition switch off, then to ON (engine off).
•  Verify related PENDING CODE or stored DTCs.
•  Is the DTC P0230:00 present?
Yes
Go to the appropriate DTC troubleshooting procedures.
(See DTC P0230:00 [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)
No
Go to the next step.
5
INSPECT WHETHER MALFUNCTION IS IN FUEL PUMP MONITOR CIRCUIT OR FUEL PUMP POWER SUPPLY CIRCUIT
•  Start the engine.
•  Does the engine start?
Yes
Go to the next step.
No
Go to Step 9.
6
CHECK FUEL PUMP MONITOR CIRCUIT FOR OPEN IN HARNESS
•  Turn the ignition switch off.
•  Remove the fuel pump relay.
•  Disconnect the PCM connector.
•  Measure the resistance between PCM terminal 1H (wiring harness-side) and fuel pump relay terminal D.
•  Is the resistance less than 5 ohm?
Yes
Go to the next step.
No
Repair for open circuit, then go to Step 12.
7
INSPECT WHETHER MALFUNCTION IS IN FUEL PUMP MONITOR CIRCUIT OR FUEL PUMP RELAY PRIMARY CIRCUIT
•  Perform the KOEO self-test.
•  Is the DTC P0231:00 present?
Yes
Go to Step 12.
No
Go to the next step.
8
CHECK FUEL PUMP MONITOR CIRCUIT INSIDE PCM
•  Turn the ignition switch off.
•  Reconnect all disconnected connectors.
•  Reinstall the fuel pump relay.
•  Turn the ignition switch to the ON position (engine off).
•  Access the PCM and monitor the FPM PID.
•  Is the PID state OFF?
Yes
Unable to duplicate or identify the cause of concern at this time.
Perform the “INTERMITTENT CONCERN TROUBLESHOOTING” procedure.
(See INTERMITTENT CONCERN TROUBLESHOOTING [MZI-3.7].)
No
Go to Step 12.
9
CHECK B+ CIRCUIT VOLTAGE TO FUEL PUMP RELAY
•  Turn the ignition switch off.
•  Remove the fuel pump relay.
•  Measure the voltage between fuel pump relay terminal C (wiring harness-side) and body ground
•  Is the voltage greater than 10 V?
Yes
Go to the next step.
No
B+ circuit concern is present.
Inspect the condition of the related fuse/fuse links.
•  If normal, repair for open circuit.
•  If the fuse/fuse link is damaged, inspect the circuit for a short to ground before installing a new fuse/fuse link.
Go to Step 12.
10
CHECK FUEL PUMP POWER SUPPLY CIRCUIT FOR OPEN IN HARNESS
•  Fuel pump relay is removed.
•  Disconnect the fuel pump unit and PCM connectors.
•  Measure the resistance between fuel pump relay terminal D and body ground
•  Is the resistance less than 10 ohms?
Yes
Replace the fuel pump relay, then go to Step 12.
No
Repair for open circuit. (The open is between the splice and the fuel pump relay.)
Go to Step 12.
11
CHECK HARNESS
•  Turn the ignition switch off.
•  Remove the fuel pump relay.
•  Disconnect the PCM connector.
•  Connect a 5 A fused jumper wire between PCM terminal 1BI (wiring harness-side) and body ground.
•  Turn the ignition switch to the ON position (engine off).
•  Measure the voltage between PCM terminal 1H (wiring harness-side) and body ground.
•  The fuel pump turns on and the PCM terminal 1H voltage will be greater than 10 V.
•  Check for an indication of a concern while carrying out the following. The voltage changes suddenly when a concern is present.
―  Shake, wiggle, and bend the B+ supply to the FP relay
―  Shake, wiggle, and bend the fuel pump power supply circuit between the fuel pump relay and the PCM terminal 1H splice
―  Lightly tap on the fuel pump relay to simulate road shock
•  Turn the ignition switch off.
•  Visually inspect the fuel pump relay and its loom connector for damage and corrosion.
•  Is a concern present?
Yes
Isolate the concern and repair if necessary.
Go to the next step.
No
Go to the next step.
(The system is operating normal at this time. The concern may have been caused by a loose or corroded connector.)
12
VERIFY TROUBLESHOOTING OF DTC P0231:00 HAS BEEN COMPLETED
•  Verify that all disconnected connectors are reconnected.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Perform the KOEO or KOER self-test.
•  Is the same DTC present?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the PCM.
Go to the next step.
No
Go to the next step.
13
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)
No
Troubleshooting completed.