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P050B






P050B-COLD START IGNITION TIMING PERFORMANCE





For a complete wiring diagram Refer to the Wiring Information.

Theory of Operation

Spark adjustment during a cold start is intended to provide quick response to idle speed variations. The spark adjust diagnostics monitors spark advance on a cold start over a period of time, then compares the average spark advance to a threshold.

- When Monitored:
Cold start condition. Ambient Air temperature between -7° C and 50° C (19.4° F and 122° F). Engine Coolant temperature between -7° C and 50° C (19.4° F and 122° F). The difference between the Ambient Air temp and ECT temp at Start is equal to or less than 10° C (50° F). Engine running at idle only.

- Set Condition:
Engine RPM is 50 RPM or more (depending on vehicle specifications), below idle speed for at least 3 seconds and the average spark advance is above the threshold, too much spark advance, for a specified time limit. Two trip fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DTC
1. Ignition on, engine not running.

NOTE: Low battery voltage can also cause excessive current draw, in very hot and very cold ambient temperatures. Make sure the battery can pass a load test before continuing.

2. Start the engine.
3. Allow the engine to reach normal operating temperature.
4. With a scan tool, select View DTCs.

NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

Is the DTC Active or Pending at this time?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition Test.

2. THROTTLE PLATE INSPECTION
1. Turn the ignition off.
2. Remove the Air Cleaner Assembly from the Throttle Body.
3. Check for any signs of a foreign material (ice, dirt, or excessive carbon build up) on the Throttle Plate or in the bore causing the Throttle Plate to stick.

Were any signs of foreign material or scoring of the throttle plate or bore found?

Yes

- Remove the debris if possible or replace the Throttle Body Assembly. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. DIRTY AIR FILTER
1. Remove and inspect the Air Filter.

Is the Air Filter dirty?

Yes

- Replace the Air Filter.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 4

4. CONTAMINATED FUEL
1. Inspect the Fuel for contamination. (Dirt, water, or other foreign material)

Is the fuel contaminated?

Yes

- Drain the Fuel from the fuel tank into an approved gas holding tank and add clean fuel. Procedures.

No

- Go To 5

5. EXCESSIVE RESISTANCE IN THE (K124) ETC POSITIVE CIRCUIT
1. Turn the ignition off.
2. Disconnect the C2 harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install PCM Pinout Box 8815 along with the Adapter 8815-1 to perform the diagnosis.

3. Using a voltmeter perform a voltage drop test. Backprobe the (K124) ETC Positive circuit at the Throttle Body harness connector and probe the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

4. Start the engine and allow it to reach normal operating temperature.
5. Monitor the voltmeter.

Is the voltage below 0.5 of a volt?

Yes

- Go To 6

No

- Repair the excessive resistance in the (K124) ETC Positive circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. EXCESSIVE RESISTANCE IN THE (K126) ETC NEGATIVE CIRCUIT
1. Turn the ignition off.
2. Move the voltmeter leads to backprobe the (K126) ETC Negative circuit at the Throttle Body harness connector and to probe the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

3. Start the engine and allow it to reach normal operating temperature.
4. Monitor the voltmeter.

Is the voltage below 0.5 of a volt?

Yes

- Go To 7

No

- Repair the excessive resistance in the (K126) ETC Negative circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

7. ETC MOTOR




1. Turn the ignition off.

NOTE: Take the following measurement using special tool #8815 to avoid possible damage to the Throttle Body harness connector.

2. Connect the Throttle Body harness connector.
3. Disconnect special tool #8815-1 from the C2 PCM harness connector.
4. Measure the resistance of the ETC Motor by probing the appropriate terminals of special tool #8815 for the (K124) ETC Positive circuit and the (K126) ETC Negative circuit.

Is the resistance between 2.5 and 25 ohms at closed throttle?

Yes

- Go To 8

No

- Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors. Replace the Throttle Body Assembly if no problems were found in the connectors. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

8. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body Assembly and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors.
4. Search for any Technical Service Bulletins that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

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