DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P050B

DTC P050B : Cold Start Ignition Timing Control System Performance Problem

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information How To Troubleshoot The Fuel And Emissions Systems.

1. PGM-FI system check:

PGM-FI system check
-1. Turn the ignition switch to ON (II).

-2. Check for Pending or Confirmed DTCs with the HDS.

Are any Pending or Confirmed DTCs other than P050B indicated?
-YES- Go to the indicated DTC's troubleshooting.
-NO- Only DTC P050B is indicated. Go to step 2.

2. Intake air duct visual check:

Intake air duct visual check
-1. Check for a poor connection or blockage at the intake air duct.

Is OK?
-YES- Go to step 3.
-NO- Reconnect or repair the intake air duct, then do the repair verification.

3. Air cleaner housing visual check:

Air cleaner housing visual check
-1. Check for a poor connection or blockage at the air cleaner housing.

Is OK?
-YES- Go to step 4.
-NO- Replace the air cleaner housing Service and Repair, then do the repair verification.

4. Air cleaner element visual check:

Air cleaner element visual check
-1. Check for dirt or debris on the air cleaner element.

Is dirty?
-YES- Replace the air cleaner element Service and Repair, then do the repair verification.
-NO- Go to step 5.

5. Problem verification:

Problem verification
-1. Let the engine cool until the value of ECT SENSOR 1 is 122 °F (50 °C) or less.

-2. Clear the DTC with the HDS.

-3. Start the engine, and let it idle for 10 seconds or more.

-4. Monitor the OBD STATUS for DTC P050B with the HDS.

Does the HDS indicate FAILED?
-YES- The failure is duplicated. Go to step 6.
-NO- If the HDS indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the CKP sensor, the throttle body, the MAF sensor/IAT sensor, ECT sensor 1, ECT sensor 2, and the ECM/PCM. If the HDS indicates EXECUTING, keep idling until a result comes on. If the HDS indicates OUT OF CONDITION, go to step 5-1. and recheck.

6. Determine possible failure area (CKP sensor, others):

Determine possible failure area (CKP sensor, others)
-1. Check the ignition timing Testing and Inspection.

Is the ignition timing OK?
-YES- Go to step 8.
-NO- Go to step 7.

7. CKP sensor and CKP pulse plate visual check:

CKP sensor and CKP sensor plate visual check:
-1. Check for damage at the CKP sensor and the CKP pulse plate.

Is the CKP sensor or the CKP pulse plate damaged?
-YES- Replace the CKP sensor CKP Sensor Removal and Installation and/or the CKP pulse plate Service and Repair, then do the repair verification.
-NO- Update the ECM/PCM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM/PCM Service and Repair, then do the repair verification.

8. Throttle body test:

Throttle body test
-1. Do the ETCS TEST with the HDS.

Is the THROTTLE ACTUATOR CONTROL VALVE normal?
-YES- The throttle body is OK. Go to step 9.
-NO- Replace the throttle body Removal and Replacement, then do the repair verification.

9. MAF sensor performance check:

MAF sensor performance check
-1. Start the engine. Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.

-2. While holding the engine speed at 2,500 rpm for 30 seconds, check the MAF SENSOR in the DATA LIST with the HDS.

Is there about 5.3-6.5 g/s?
-YES- The MAF sensor is OK. Go to step 10.
-NO- Replace the MAF sensor/IAT sensor Service and Repair, then do the repair verification.

10. ECT sensor 1 and ECT sensor 2 performance check:

ECT sensor 1 and ECT sensor 2 performance check
-1. Turn the ignition switch to LOCK (0).

-2. Allow the engine to cool to the ambient temperature.

-3. Note the ambient temperature.

-4. Turn the ignition switch to ON (II).

-5. Quickly note the value of ECT SENSOR 1 and ECT SENSOR 2 in the DATA LIST with the HDS.

-6. Compare the value of ECT SENSOR 1 and the value of ECT SENSOR 2 to the ambient temperature individually.

Does either sensor differ more than 5.4 °F (3 °C) from the ambient temperature?
-YES- Replace the sensor that differed more than 5.4 °F (3 °C) from the ambient temperature, then do the repair verification.
-NO- The ECT sensors are OK. Check and repair any problems with the following items. Repair or replace them if needed, then do the repair verification. If every item is OK, update the ECM/PCM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM/PCM Service and Repair, then do the repair verification.
* Engine compression and cylinder leakdown
* Valve pause system
* Engine oil
* A/C system

Repair verification (OBD STATUS check):

-1. Turn the ignition switch to LOCK (0).

-2. Reconnect all connectors.

-3. Turn the ignition switch to ON (II).

-4. Reset the ECM/PCM with the HDS How To Troubleshoot The Fuel And Emissions Systems.

-5. Do the ECM/PCM idle learn procedure ECM/PCM Idle Learn Procedure.

-6. Let the engine cool until the value of ECT SENSOR 1 is 122 °F (50 °C) or less.

-7. Start the engine, and let it idle for 10 seconds or more.

-8. Monitor the OBD STATUS for DTC P050B in the DTCs MENU with the HDS.

Does the HDS indicate PASSED, FAILED, EXECUTING, or OUT OF CONDITION?
-PASSED- Troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.
-FAILED- Go to step 1 and recheck. If the ECM/PCM was updated, substitute a known-good ECM/PCM Service and Repair, then check the OBD STATUS again.
-EXECUTING- Keep the test condition until a result comes on.
-OUT OF CONDITION- Meet the test condition, and check the OBD STATUS again.