DTC P0231:00 [MZI-3.7]

id0102d2505300

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. (See KOEO/KOER SELF TEST [MZI-3.7].) • 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].)
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. (See KOEO/KOER SELF TEST [MZI-3.7].) • 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. (See ON-BOARD DIAGNOSTIC TEST [MZI-3.7].) • 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. (See KOEO/KOER SELF TEST [MZI-3.7].) • Is the same DTC present? | Yes | Repeat the inspection from Step 1. • If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZI-3.7].) Go to the next step.
No | Go to the next step.
13 | VERIFY AFTER REPAIR PROCEDURE • Perform the “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [MZI-3.7].) • Are any DTCs present? | Yes | Go to the applicable DTC inspection. (See DTC TABLE [MZI-3.7].)
No | Troubleshooting completed.