P1400

DTC P1400

DTC DESCRIPTOR

DTC P1400
Cold Start Emission Reduction Control System

DIAGNOSTIC FAULT INFORMATION
Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
The catalytic converter must be warmed to efficiently reduce the emissions. The cold start strategy is to reduce the amount of time it takes to warm the catalytic converter. During a cold start, the engine idle speed is elevated and spark timing is retarded to allow the catalyst to warm quickly. This diagnostic monitors the following to build an exhaust energy model:
- Throttle position (TP) sensor
- Manifold absolute pressure (MAP) sensor
- Barometric pressure (BARO)
- Mass air flow (MAF) sensor
- Engine coolant temperature (ECT) sensor
- Intake air temperature (IAT) sensor
- Ignition control

The actual model is then compared to the expected exhaust energy model.

CONDITIONS FOR RUNNING THE DTC
- The engine is running, and a cold start has been detected
- Vehicle speed less than 2 Km/h
- Throttle position sensor less than 2 percent
- Airflow per cylinder greater than 40 mg
- DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0335, P0336, P0351, P0352, P0353, P0501, P0502, P0506, P0507, P0601, P0602, P0603, P0604, P0606, P0607, P062F, P0641, P0651, P1101, P1516, P1682, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138, P2176, P2610 are not set.

CONDITIONS FOR SETTING THE DTC
- The average accumulated exhaust energy model is not within a calibrated range to the estimated average exhaust energy model. The average accumulated exhaust energy is less than -8 kJ/s or greater than 0.37 kJ/s of the estimated average accumulated exhaust energy.
- This DTC runs within 15 seconds of start up. This diagnostic runs once per trip when a cold start has been determined.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

CIRCUIT/SYSTEM VERIFICATION
Allow the engine to cool. Monitor the Cold Startup parameter, this should indicate Yes. Start and idle the engine for at least 30 seconds. DTC P1400 should run and pass.

CIRCUIT/SYSTEM TESTING
- Inspect the air intake system for the following:
- Modified, damaged, or restricted
- Dirty or deteriorating air filter element
- Crankcase ventilation system for correct operation-Refer to Crankcase Ventilation System Inspection/Diagnosis. Testing and Inspection
- Water intrusion
- Vacuum leak and other un-metered air downstream of the MAF sensor
- Intake manifold leak
- Inspect the exhaust system for the following:
- Water intrusion
- Exhaust leak
- Damaged, restricted, modified or enhanced exhaust system-Refer to Symptoms - Exhaust System. Symptom Related Diagnostic Procedures
- Inspect the engine mechanical for items that could alter the air flow into the combustion chamber. Refer to Symptoms - Engine. Symptom Related Diagnostic Procedures