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
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Ignition Coil Supply Voltage Circuit Bank 1
Diagnostic Fault Information
Circuit/System Description
The ignition system on this engine uses an individual module/coil for each cylinder. The engine control module (ECM) monitors the ignition voltage from the fuse of each bank of coils to the ECM. The ECM uses this information to determine if the misfire is ignition coil voltage related.
Conditions for Running the DTC
* The ignition is ON.
* The ignition module supply voltage is less than 2.5 V.
* The DTCs run continuously when the above condition is met.
Conditions for Setting the DTC
The ECM detects a fault in an ignition coil control circuit for 50 out of 63 samples. Each sample runs on a 6.25 ms loop.
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 (LE9) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left (DH6)
Description and Operation
* Electronic Ignition System Description Description and Operation
* Engine Control Module Description Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Engine Control Module Scan Tool Information (LFX or LFW) Engine Control Module Scan Tool Information (LFX or LFW)Engine Control Module Scan Tool Information (LE9) Engine Control Module Scan Tool Information (LE9)
Circuit/System Verification
With the ignition ON, observe the Ignition Coil Supply Voltage Bank 1 parameter for each cylinder.
The parameter should display ON.
Circuit/System Testing
Note:
The ignition circuit supplies voltage to other components. Make sure you test all circuits for a short to ground or test all components for being shorted that share the ignition circuit.
1. Ignition OFF, disconnect the harness connector at the appropriate T8 ignition coil.
2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal D and ground of each T8 ignition coil.
• If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance.
• If the circuit tests normal, with the ignition OFF, disconnect the harness connector at each T8 ignition coil and monitor the fuse while individually connecting each T8 ignition coil. If the fuse opens, replace the appropriate T8 ignition coil.
3. Ignition OFF, disconnect the K20 ECM harness connector X1.
4. Ignition ON, connect a test lamp between the X1 67 ignition voltage circuit and ground. The test lamp should illuminate on each circuit.
• If the test lamp does not illuminate, test the ignition circuit for an open/high resistance.
5. If all circuits/connections test normal, replace the K20 ECM.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Ignition Coil Replacement Service and Repair
* Control Module References Control Module References for K20 ECM replacement, setup, and programming