P135A

DTC P135A

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 P135A
- Ignition Coil Supply Voltage Circuit Bank 1

Diagnostic Fault Information






Circuit/System Description

The ignition system uses an individual ignition coil for each cylinder. The engine control module (ECM) monitors the ignition voltage from the fuse to the individual coils.

Conditions for Running the DTC

* The ignition is ON.

* Ignition Run/Crank and PT relay voltages are greater than 11 V

The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects less than 2.5 V on the ignition coil supply voltage circuit for greater than 313 ms.

Action Taken When the DTC Sets

DTC P135A is a Type A DTC.

Conditions for Clearing the DTC

DTC P135A is a Type A DTC.

Reference Information

Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views Outside Rearview Mirror - Driver

Description and Operation

Electronic Ignition System Description Description and Operation

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

Scan Tool Reference

Control Module References Control Module References

Circuit/System Verification

1. Ignition ON.

2. Verify the scan tool Ignition Coil Supply Voltage parameter displays ON.

• If ON is not displayed
Refer to Circuit/System Testing.

• If ON is displayed

3. 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.

4. Verify DTC P135A is not set.

• If the DTC is set
Refer to Circuit/System Testing.

• If the DTC is not set

5. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module, ignition ON.

2. Verify a test lamp illuminates between the ignition circuit terminal 62 and ground.

• If the test lamp does not illuminate and the circuit fuse is good

1. Ignition OFF.

2. Test for less than 2 ohms in the ignition circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.

• If the test lamp does not illuminate and the circuit fuse is open

Note: The ignition circuit supplies voltage to other components. Make sure to test all circuits and components for a short to ground that share the ignition circuit.

1. Ignition OFF, disconnect all T 8 Ignition Coils.

2. Test for infinite resistance between the ignition circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Replace the fuse, ignition ON

4. Verify the fuse is good after connecting each T 8 Ignition Coil one at a time.

• If the fuse opens, replace the T 8 Ignition Coil that opens the fuse when connected.

• If the fuse is good, replace the K20 Engine Control Module.

• If the test lamp illuminates

3. Replace the K20 Engine Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Ignition Coil Replacement Service and Repair

* Control Module References Control Module References for engine control module replacement, programming, and setup