DTC P0645:00 [MZI-3.7]

id0102d2588000

DTC P0645:00 | A/C relay control circuit
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DETECTION CONDITION | • Monitors the A/C relay control circuit output from the PCM. The test fails when the PCM grounds the A/C relay control circuit, excessive current draw is detected on the A/C relay control circuit; or, with the A/C relay control circuit not grounded by the PCM, voltage is not detected on the A/C relay control circuit (the PCM expects to detect vehicle power voltage coming through the A/C relay coil to the A/C circuit).
POSSIBLE CAUSE | • A/C relay connector or terminal malfunction • Open circuit in wiring between main relay terminal No.1 D and A/C relay terminal A • Short to power supply between A/C relay terminal E and PCM terminal 1W • Short to ground in wiring between A/C relay terminal E and PCM terminal 1W • PCM connector or terminal malfunction • Open circuit in wiring between A/C relay terminal E and PCM terminal 1W • A/C relay malfunction • PCM malfunction

Diagnostic procedure

STEP | INSPECTION | ACTION
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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 | INSPECT THAT THE ACCS PID IS OFF • Turn ignition key to ON (Engine running). • A/C switch and defroster switch off. • Access the ACCS PID using M-MDS. • Is the PID state off? | Yes | Go to the next step.
No | ACCS input to PCM is requesting A/C. Inspect A/C system operation, then go to Step 12. (See DIAGNOSTIC TROUBLE CODE NUMBER INSPECTION.) (See TROUBLESHOOTING INDEX.)
4 | INSPECT A/C RELAY CONNECTOR FOR POOR CONNECTOR • Turn the ignition switch off. • Disconnect the A/C relay connector. • Inspect for poor connection (such as damaged, pulled-out pins, corrosion, etc.). • Are there any malfunction? | Yes | Repair or replace suspected part, then go to Step 12.
No | Go to the next step.
5 | INSPECT A/C RELAY POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT • Turn the ignition switch to the ON position (Engine off). • Measure voltage between A/C relay terminal A (wiring harness-side) and body ground. • Is voltage B+? | Yes | Go to the next step.
No | Repair or replace suspected part, then go to Step 12.
6 | INSPECT A/C RELAY CONTROL CIRCUIT FOR SHORT TO POWER SUPPLY • Turn the ignition switch to the ON position (Engine off). • Remove the A/C relay. • Measure voltage between A/C relay terminal E (wiring harness-side) and body ground. • Is voltage B+? | Yes | Repair or replace suspected part, then go to Step 12.
No | Go to the next step.
7 | INSPECT A/C RELAY CONTROL CIRCUIT FOR SHORT TO GROUND • Install the A/C relay. • Turn the ignition switch off. • Inspect continuity between A/C relay terminal E (wiring harness-side) and body ground. • Is there continuity? | Yes | Repair or replace suspected part, then go to Step 12.
No | Go to the next step.
8 | INSPECT PCM CONNECTOR FOR POOR CONNECTION • Turn ignition switch to off. • Disconnect the PCM connector. • Inspect for poor connection (such as damaged, pulled-out pins, corrosion). • Is there any malfunction? | Yes | Repair or replace suspected part, then go to Step 12.
No | Go to the next step.
9 | INSPECT A/C RELAY CONTROL CIRCUIT FOR OPEN CIRCUIT • PCM connector is disconnected. • Turn the ignition switch off. • Inspect continuity between A/C relay terminal E (wiring harness-side) and PCM terminal 1W (wiring harness-side). • Is there continuity? | Yes | Go to the next step.
No | Repair or replace suspected part, then go to Step 12.
10 | INSPECT A/C RELAY • Inspect A/C relay. (See RELAY INSPECTION.) • Is A/C relay normal? | Yes | Go to the next step.
No | Replace the A/C relay. Start the engine. Turn on the A/C switch. Wait for 15 s. Turn off the A/C switch, then go to Step 12.
11 | INSPECT FOR CORRECT PCM OPERATION • Disconnect all the PCM connectors. • Visually inspect for: ― Pushed out pins ― Corrosion • Connect all the PCM connectors and verify that they seat correctly. • Retrieve DTCs using the M-MDS. • Is the PENDING CODE for this DTC present? | Yes | Go to the next step.
No | The system is correctly. Go to the next step.
12 | VERIFY TROUBLESHOOTING OF DTC P0645:00 HAS BEEN COMPLETED • Verify that all disconnected connectors 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 PENDING CODE for the 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.