Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P1400: Cold Start Emission Reduction Control SystemCircuit/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:
| • | Engine speed |
| • | Spark advance |
| • | Throttle position |
| • | Engine airflow |
| • | Engine coolant temperature |
| • | Engine run time |
| • | Park/Neutral position |
| • | Vehicle speed |
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. |
| • | The vehicle speed is less than 2 km/h (1 mph). |
| • | The throttle position sensor is less than 2 percent. |
| • | The airflow per cylinder is greater than 80 mg. |
| • | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0201, P0202, P0203, P0204, P0300, P0335, P0336, P0351, P0352, P0353, P0506, P0507, P0601, P0602, P0603, P0604, P0606, P0607, P062F, P0641, P0651, P1516, P1682, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138, P2176, P2610 are not set. |
Conditions for Setting the DTC
This DTC runs within 15 seconds within the first 2 minutes of start-up. This diagnostic runs once per trip when a cold start has been determined.
Action Taken When the DTC Sets
DTC P1400 is a Type A DTC.
Conditions for Clearing the MIL/DTC
DTC P1400 is a Type A DTC.
Diagnostic Aids
Any loading of the engine that lowers engine RPM, such as partial application of the clutch, A/C cycling, etc. during the first 120 seconds of the engine run time may set this DTC.
Circuit/System Verification
| • | Allow the engine to cool. |
| • | Start and idle the engine for at least 2 minutes. |
| • | DTC P1400 should run and pass. |
| • | Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. |
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. |
| - | Water intrusion |
| - | Vacuum leak and other unmetered 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. |
| • | Inspect the engine mechanical for items that could alter the air flow into the combustion chamber. |
