P135A
DTC P135A or P135B
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 Positive Voltage Circuit Bank 1
DTC P135B
- Ignition Coil Positive Voltage Circuit Bank 2
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.
* The ignition module supply voltage is less than 2.5 V.
* Ignition Run/Crank and PT relay voltages are greater than 11 V
* The DTCs run continuously when the above condition is met.
Conditions for Setting the DTC
The ECM detects a fault in the ignition coil supply voltage circuit for greater than 313 ms.
Action Taken When the DTC Sets
DTC P135A and P135B are Type A DTCs.
Conditions for Clearing the DTC
DTC P135A and P135B are Type A DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics (LFX) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly - Primary
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 appropriate 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 or P135B 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 appropriate ignition circuit terminal listed below and ground.
* Terminal 62
* Terminal 67
• 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 - Bank 1 Ignition Coil Replacement - Bank 1
* Ignition Coil Replacement - Bank 2 Ignition Coil Replacement - Bank 2
* Control Module References Control Module References for engine control module replacement, programming, and setup