GM Service Manual Online
For 1990-2009 cars only

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 provides an overview of each diagnostic category.

DTC Descriptors

DTC P0201: Injector 1 Control Circuit

DTC P0202: Injector 2 Control Circuit

DTC P0203: Injector 3 Control Circuit

DTC P0204: Injector 4 Control Circuit

DTC P0261: Injector 1 Control Circuit Low Voltage

DTC P0264: Injector 2 Control Circuit Low Voltage

DTC P0267: Injector 3 Control Circuit Low Voltage

DTC P0270: Injector 4 Control Circuit Low Voltage

DTC P2146: Injector Positive Voltage Control Circuit Group 1

DTC P2147: Injector Positive Voltage Control Circuit Group 1 Low Voltage

DTC P2148: Injector Positive Voltage Control Circuit Group 1 High Voltage

DTC P2149: Injector Positive Voltage Control Circuit Group 2

DTC P2150: Injector Positive Voltage Control Circuit Group 2 Low Voltage

DTC P2151: Injector Positive Voltage Control Circuit Group 2 High Voltage

DTC P2152: Injector Positive Voltage Control Circuit Group 3

DTC P2153: Injector Positive Voltage Control Circuit Group 3 Low Voltage

DTC P2154: Injector Positive Voltage Control Circuit Group 3 High Voltage

DTC P2155: Injector Positive Voltage Control Circuit Group 4

DTC P2156: Injector Positive Voltage Control Circuit Group 4 Low Voltage

DTC P2157: Injector Positive Voltage Control Circuit Group 4 High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Direct Fuel Injector High Voltage Supply Cylinder 1

P0300, P0301, P0304, P2146, P2155

P0201, P0300, P0301, P0304

P0300, P0301, P0304, P2146, P2155

Direct Fuel Injector High Voltage Supply Cylinder 2

P0300, P0302, P0303, P2149, P2152

P0202, P0300, P0302, P0303

P0300, P0302, P0303, P2149, P2152

Direct Fuel Injector High Voltage Supply Cylinder 3

P0300, P0302, P0303, P2149, P2152

P0203, P0300, P0302, P0303

P0300, P0302, P0303, P2149, P2152

Direct Fuel Injector High Voltage Supply Cylinder 4

P0300, P0301, P0304, P2146, P2155

P0204, P0300, P0301, P0304

P0300, P0301, P0304, P2146, P2155

Direct Fuel Injector High Voltage Control Cylinder 1

P0261, P0300, P0301

P0201, P0300, P0301

P0300, P0301

Direct Fuel Injector High Voltage Control Cylinder 2

P0264, P0300, P0302

P0202, P0300, P0302

P0300, P0302

Direct Fuel Injector High Voltage Control Cylinder 3

P0267, P0300, P0303

P0203, P0300, P0303

P0300, P0303

Direct Fuel Injector High Voltage Control Cylinder 4

P0270, P0300, P0304

P0204, P0300, P0304

P0300, P0304

Circuit/System Description

The engine control module (ECM) supplies voltage to each fuel injector on the injector high voltage supply circuits. The ECM energizes each fuel injector by grounding the high voltage control circuit of that fuel injector. The ECM monitors the status of the injector high voltage supply circuits and the fuel injector high voltage control circuits. When a fuel injector circuit condition is detected by the ECM, the affected fuel injector will be disabled.

Conditions for Running the DTC

    • The engine speed is greater than 80 RPM.
    • The ignition 1 signal parameter is between 8-18V.
    • The DTCs run continuously within the enabling conditions.

Conditions for Setting the DTC

The control module detects an incorrect voltage on the high voltage supply circuit or the high voltage control circuit for greater than 1 second.

Action Taken When the DTC Sets

DTCs P0201, P0202, P0203, P0204, P0261, P0264, P0267, P0270, P2146, P2147, P2148, P2149, P2150, P2151, P2152, P2153, P2154, P2155, P2156, and P2157 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0201, P0202, P0203, P0204, P0261, P0264, P0267, P0270, P2146, P2147, P2148, P2149, P2150, P2151, P2152, P2153, P2154, P2155, P2156, and P2157 are Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Component Connector End Views
    •  Inline Harness Connector End Views

Description and Operation

Fuel System Description

Electrical Information Reference

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

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Observe the Misfire Current Counters with a scan tool. The Misfire Current Counters should not be incrementing.
  2. Engine operating, observe the DTC information with a scan tool. DTCs P0201, P0202, P0203, P0204, P0261, P0264, P0267, P0270, P2146, P2147, P2148, P2149, P2150, P2151, P2152, P2153, P2154, P2155, P2156, and P2157 should not set.
  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. Ignition OFF, disconnect the X145 fuel injector multi-way harness connector.
  2. Inspect the X145 fuel injector multi-way harness connector for proper connection, proper terminal contact, and proper terminal retention force.
  3. If a condition is found, repair the poor connection at the X145 connector.
  4. Engine cranking, verify that a test lamp flashes brightly between ground and the high voltage supply circuit terminal, ECM side of the connector, of the appropriate fuel injector listed below.
  5. • Q17A injector 1 terminal 7
    • Q17B injector 2 terminal 8
    • Q17C injector 3 terminal 9
    • Q17D injector 4 terminal 10
    If the test lamp is always ON, test the appropriate fuel injector high voltage supply circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
    If the test lamp is always OFF, test the appropriate fuel injector high voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. Engine cranking, verify that a test lamp flashes dimly between B+ and the high voltage control circuit terminal, ECM side of the connector, of the appropriate fuel injector listed below.
  7. • Q17A injector 1 terminal 1
    • Q17B injector 2 terminal 2
    • Q17C injector 3 terminal 3
    • Q17D injector 4 terminal 4
    If the test lamp is always ON, test the appropriate fuel injector high voltage control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
    If the test lamp is always OFF, test the appropriate fuel injector high voltage control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  8. Ignition OFF, test for continuity between the suspected high voltage supply circuit and the remaining high voltage supply circuits, engine side of the connector. The DMM should display OL.
  9. • Q17A injector 1 terminal 7
    • Q17B injector 2 terminal 8
    • Q17C injector 3 terminal 9
    • Q17D injector 4 terminal 10
    If less than the specified value, repair the high voltage supply circuit for a short to the high voltage supply circuit.
  10. Ignition OFF, verify that a test lamp does not illuminate between the appropriate high voltage supply circuit terminal listed below, engine side of the connector, and B+.
  11. • Q17A injector 1 terminal 7
    • Q17B injector 2 terminal 8
    • Q17C injector 3 terminal 9
    • Q17D injector 4 terminal 10
    If the test lamp illuminates, repair the high voltage supply circuit for a short to ground.
  12. Ignition OFF, test for continuity between the suspected high voltage control circuit and the high voltage supply circuits listed below, engine side of the connector. The DMM should display OL.
  13. • Q17A injector 1 terminal 7
    • Q17B injector 2 terminal 8
    • Q17C injector 3 terminal 9
    • Q17D injector 4 terminal 10
    If less than the specified value, repair the high voltage control circuit for a short to the high voltage supply circuit.
  14. Ignition OFF, verify that a test lamp does not illuminate between the appropriate high voltage control circuit terminal listed below, engine side of the connector, and B+.
  15. • Q17A injector 1 terminal 1
    • Q17B injector 2 terminal 2
    • Q17C injector 3 terminal 3
    • Q17D injector 4 terminal 4
    If the test lamp illuminates, repair the high voltage control circuit for a short to ground.
  16. Ignition OFF, test for 1.5-4Ω between the appropriate fuel injector high voltage supply circuit terminal and the fuel injector high voltage control circuit terminal, engine side of the connector, of the appropriate fuel injector listed below.
  17. • Q17A injector 1 terminals 1 and 7
    • Q17B injector 2 terminals 2 and 8
    • Q17C injector 3 terminals 3 and 9
    • Q17D injector 4 terminals 4 and 10
    If the resistance is not within the specified range, test for an open/high resistance between X145 and the appropriate fuel injector harness connector. If the circuits test normal, test or replace the fuel injector.

Component Testing

Verify the resistance of each fuel injector with one of the following methods:

    • If the engine coolant temperature (ECT) sensor is between 10-32°C (50-90°F), the resistance of each fuel injector should be 1.25-1.75Ω.
       ⇒If not within the specified range, replace the fuel injector.
    • If the ECT sensor is not between 10-32°C (50-90°F), measure and record the resistance of each fuel injector with a DMM. Subtract the lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal to or less than 0.45Ω.
       ⇒If the difference is more than 0.45Ω, add all of the fuel injector resistance values to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average resistance value. Replace the fuel injector that displays the greatest difference above or below the average.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Sumitomo Connectors
    •  Control Module References for ECM replacement, setup, and programming