For 1990-2009 cars

### 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 provide an overview of each diagnostic category.

### DTC Descriptor

DTC P1400: Cold Start Emission Reduction Control System

### 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:

• | 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

• | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0114, P0116, P0117, P0118, P0121, P0122, P0123, P0222, P0223, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0335, P0336, P0351, P0352, P0353, P0354, P0502, P0503, P0506, P0507, P0641, P0651, P0697, P06A3, P0806, P0807, P080A, P2122, P2123, P2125, P2127, P2128, P2135, P2138, and P2544 are not set.

• | The engine is idling less than 30 seconds.

• | The ECT sensor is greater than -10°C (14°F).

• | The calculated three-way catalytic converter temperature is less than 350°C (662°F).

• | The ECM will exit the diagnostic if the calculated three-way catalytic converter temperature is greater than 420°C (788°F) when the engine run time is greater than 30 seconds.

• | The ECM will exit the diagnostic if the engine run time is greater than 90 seconds.

• | The vehicle speed is less than 2 km/h (1 mph).

• | The engine is at idle with no input from the accelerator pedal.

• | The clutch pedal position switch is less than 10 percent or greater than 80 percent - manual transmissions only

This DTC runs within the first 90 seconds of start-up. This diagnostic runs once per trip when a cold start has been determined.

### Conditions for Setting the DTC

The actual exhaust energy model does not match the expected exhaust energy model.

### 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.

### Reference Information

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition OFF, allow the engine to cool.
2. Engine idling for at least 2 minutes, observe the scan tool DTC information. DTC P1400 should run and pass.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Inspect the air intake system for the following:

• | Damage, restriction, or modification

• | Dirty or deteriorating air filter element

• | Crankcase ventilation system for correct operation--Refer to Crankcase Ventilation System Inspection/Diagnosis.

• | Water intrusion

• | Vacuum leak and other un-metered air downstream of the mass air flow (MAF) sensor

• | Intake manifold leak

2. Inspect the exhaust system for the following:

• | Water intrusion

• | Exhaust leak

• | Damaged, restricted, or modified exhaust system--Refer to Symptoms - Engine Exhaust.

3. Inspect for an engine mechanical condition that could alter the air flow into the combustion chamber. Refer to Symptoms - Engine Mechanical.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.