DTC Troubleshooting
DTC P050B: Cold Start Ignition Timing Control System Performance ProblemNOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
1. Turn the ignition switch ON (II).
2. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs other than P050B indicated?
YES - Go to the indicated DTCs troubleshooting.
NO - Go to step 3.
3. Check for poor connections or blockage at the intake air duct.
Is it OK?
YES - Go to step 4.
NO - Reconnect or repair the intake air duct, then go to step 25.
4. Check for damage at the air cleaner housing.
Is it OK?
YES - Go to step 5.
NO - Replace the air cleaner housing, then go to step 25.
5. Check for dirt or debris in the air cleaner element.
Is it dirty?
YES - Replace the air cleaner element or remove the debris, then go to step 25.
NO - Go to step 6.
6. Let the engine cool until the value of ECT SENSOR 1 is 122 °F (50 °C) or less.
7. Clear the DTC with the HDS.
8. Start the engine, and let it idle for 10 seconds or more.
9. Monitor the OBD STATUS for DTC P050B in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES - Go to step 10.
NO - If the screen indicates PASSED, intermittent failure, the system is OK at this time. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 6.
10. Inspect the ignition timing.
Is the ignition timing OK?
YES - Go to step 12.
NO - Go to step 11.
11. Check for damage at the CKP sensor and the CKP sensor pulser plate.
Is the CKP sensor and/or the CKP sensor pulser plate damaged?
YES - Replace the CKP sensor and/or the CKP sensor pulser plate, then go to step 6.
NO - Go to step 31.
12. Do the ETCS TEST in the INSPECTION MENU with the HDS.
Is the THROTTLE ACTUATOR CONTROL VALVE normal?
YES - Go to step 13.
NO - Replace the throttle body, then go to step 25.
13. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.
14. Monitor the ENGINE SPEED in the DATA LIST with the HDS, and hold the engine speed at 2,500 rpm for at least 30 seconds.
15. While holding the engine speed at 2,500 rpm, check the MAF SENSOR in the DATA LIST with the HDS.
Is there about 5.7-8.3 gm/s?
YES - Go to step 16.
NO - Replace the MAF sensor/IAT sensor, then go to step 25.
16. Turn the ignition switch OFF.
17. Drain the coolant.
18. Remove ECT sensor 1, and ECT sensor 2.
19. Allow the sensors to cool to ambient temperature.
20. Note the ambient temperature.
21. Connect ECT sensor 1 to its 2P connector, and ECT sensor 2 to its 2P connector, but do not install them on the engine.
22. Turn the ignition switch ON (II).
23. Note the value of ECT SENSOR 1 and ECT SENSOR 2 quickly in the DATA LIST with the HDS.
24. Compare the value of ECT SENSOR 1 and the ambient temperature, and the value of ECT SENSOR 2 and 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 go to step 25.
NO - Check and repair any problems with the following items, then go to step 25.
- Engine compression and cylinder leakdown
- VTEC system
- Engine oil
- A/C system
- Power steering
25. Turn the ignition switch ON (II).
26. Reset the ECM with the HDS.
27. Do the ECM idle learn procedure.
28. Let the engine cool until the value of ECT SENSOR 1 is 122 °F(50 °C) or less.
29. Start the engine, and let it idle for 10 seconds or more.
30. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P050B indicated?
YES - 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, then go to step 1.
NO - Go to step 31.
31. Monitor the OBD STATUS for DTC P050B in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 30, go to the indicated DTCs troubleshooting.
NO - If the screen indicates FAILED, 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, then go to step 1. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 28.
32. Update the ECM if it does not have the latest software, or substitute a known-good ECM.
33. Do the ECM idle learn procedure.
34. Let the engine cool until the value of ECT SENSOR 1 is 122 °F (50 °C) or less.
35. Start the engine, and let it idle for 10 seconds or more.
36. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P050B indicated?
YES - 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. If the ECM was updated, substitute a known-good ECM, then go to step 34. If the ECM was substituted, go to step 1.
NO - Go to step 37.
37. Monitor the OBD STATUS for DTC P050B in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. If any other Temporary DTCs or DTCs were indicated in step 36, go to the indicated DTCs troubleshooting.
NO - If the screen indicates FAILED, 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. If the ECM was updated, substitute a known-good ECM, then go to step 34. If the ECM was substituted, go to step 1. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 34.