P1400

DTC P1400 (LUW)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor
DTC P1400
- Cold Start Emission Reduction Control System

Circuit/System Description

The catalyst must be warmed to efficiently reduce the emissions. The cold start strategy is to reduce the amount of time it takes to warm the catalyst. 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, and P2138 are not set.
* The engine is idling less than 30 s.
* The Engine Coolant Temperature (ECT) sensor is greater than -10°C (14°F).
* The calculated three way catalyst temperature is less than 350°C (662°F).
* The ECM will exit the diagnostic if the calculated three way catalyst temperature is greater than 420°C (788°F) when the engine run time is greater than 30 s.
* The ECM will exit the diagnostic if the engine run time is greater than 90 s.
* 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% or greater than 80%, manual transmissions only.

This DTC runs within the first 90 s 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 DTC

DTC P1400 is a Type A DTC.

Reference Information
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference

Control Module References 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 min, 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 (LDE, LED, LFJ, LXV, 2H0, LUW, LFH) Testing and Inspection
* Water intrusion
* Vacuum leak and other unmetered 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 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 Symptoms - Engine Mechanical

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.