• 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.

When the ignition is activated to start the vehicle, a discrete signal is supplied to the engine control module (ECM). The ECM then verifies that the clutch pedal is pressed or the transmission is in park/neutral. If it is, the ECM then supplies 12 V to the control circuit of the starter drive pinion relay. When this occurs, battery voltage is supplied through the switch of the starter relay to the starter pinion.

• The ignition is activated to START.
• The system voltage is between 9.5–18 V.

The ECM detects improper voltage on the control circuit of the starter relay.

DTC P26E4, P26E5, and P26E6 are C type DTCs.

DTC P26E4, P26E5, and P26E6 are C type DTCs.

Starting and Charging Schematics

Master Electrical Component List

Starting System Description and Operation

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

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Control Module References for scan tool information

1. Ignition OFF and all vehicle systems OFF, disconnect the KR27C Starter Pinion Solenoid Actuator Relay. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 Ω between the ground circuit terminal 85 and ground.
• If 10 Ω or greater
1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, repair the open/high resistance in the ground connection.
• If less than 10 Ω
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
• If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF.
2. Test for less than 2 Ω in the B+ circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, verify the fuse is good and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the B+ circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance,
3. Test for infinite resistance between the control circuit terminal 87 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the M64 Starter Motor.
• If the test lamp illuminates
5. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.

Note: If the Starter Pinion Relay command is not available in the scan tool, verify the test lamps turns on and off when cycling the ignition between the OFF and CRANK position with the parking brake set and clutch pedal pressed (manual transmission) or the transmission in park (automatic transmission).

6. Verify the test lamp turns ON and OFF when commanding the Starter Pinion Relay ON and OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K20 Engine Control Module.
• If the test lamp is always ON
1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 Engine Control Module.
• If the test lamp turns ON and OFF
7. Ignition ON, connect a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87.
8. Verify the M64 Starter Motor is activated.
• If the M64 Starter Motor does not activate
1. Ignition OFF, disconnect the harness connector at the M64 Starter Motor.
2. Test for infinite resistance between the control circuit terminal X1 2 or X1 B and ground..
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the M64 Starter Motor.
• If the M64 Starter Motor activates
9. Test or replace the KR27C Starter Pinion Solenoid Actuator Relay.

1. Ignition OFF, disconnect the appropriate relay.
2. Test for 70–150 Ω between terminals (85 or 1) and (86 or 2).
• If less than 70 or greater than 150 Ω

  Replace the relay.

• If between 70–150 Ω
3. Test for infinite resistance between the terminals listed below:
• (30 or 3) and (86 or 2)
• (30 or 3) and (87 or 5)
• (30 or 3) and (85 or 1)
• (85 or 1) and (87 or 5)
• (86 or 2) and (87 or 5)
• If less than infinite resistance

  Replace the relay.

• If infinite resistance
4. Install a 3 A fused jumper wire between relay terminal (85 or 1) and 12 V. Install a jumper wire between relay terminal (86 or 2) and ground.
5. Test for less than 5.0 Ω between terminals (30 or 3) and (87 or 5).
• If 5.0 Ω or greater

  Replace the relay.

• If less than 5.0 Ω
6. All OK

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for control module replacement, programming, and setup.