The engine control module (ECM)/powertrain control module (PCM) controls engine cranking based on a power mode input and the status of the clutch start switch (manual transmission) or the park/neutral position (PNP) switch (automatic transmission).

With the transmission in Park/Neutral or the clutch depressed, voltage at the ECM/PCM PNP/clutch start switch signal circuit is high. This indicates to the ECM/PCM that conditions are acceptable for cranking. When a power mode crank request is seen, the ECM/PCM grounds the starter relay coil control circuit. This energizes the coil side of the relay, which pulls the switch side of the relay closed, applying voltage to the starter S-terminal and engaging the starter solenoid.

A misadjusted PNP switch or clutch start switch may result in a starter solenoid does not click condition. The adjustment process can be found in the replacement procedure for the component.

Schematic Reference

Starting and Charging Schematics

Connector End View Reference

Engine Electrical Connector End Views

Description and Operation

Starting System Description and Operation

Electrical Information Reference

Scan Tool Reference

Automatic Transmission

1. Ignition ON, transmission in Park or Neutral, verify the scan tool PNP Switch parameter reads Park/Neutral.

⇒	If not the specified value refer to PNP Switch Circuit Malfunction.

2. Command the Starter Relay ON with a scan tool. The starter solenoid should engage and the engine should crank.

⇒	If the solenoid does not engage, refer to Crank Relay Circuit Malfunction.

⇒	If the solenoid engages but the engine does not crank, refer to Starter Solenoid Clicks, Engine Does Not Crank .

Manual Transmission

1. Ignition ON, clutch pedal depressed, verify the scan tool Clutch Start Switch (RPO LE5 and RPO L61) or Clutch Pedal Switch (RPO LSJ) parameter reads Applied.

⇒	If not the specified value refer to Clutch Start Switch Circuit Malfunction.

2. Command the Starter Relay ON with a scan tool. The starter solenoid should engage and the engine should crank.

⇒	If the solenoid does not engage, refer to Crank Relay Circuit Malfunction.

⇒	If the solenoid engages but the engine does not crank, refer to Starter Solenoid Clicks, Engine Does Not Crank .

PNP Switch Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the PNP switch.
2. Ignition ON, verify a test lamp illuminates between the ignition circuit terminal 12 and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

3. Verify the scan tool PNP Switch parameter reads In Gear.

⇒	If not the specified value, test the signal circuit terminal 12 for a short to voltage. If the circuit tests normal, replace the ECM.

4. Install a 3A fused jumper wire between the ignition circuit terminal 12 and the signal circuit terminal 1. Verify the scan tool PNP Switch parameter reads Park/Neutral.

⇒	If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the PNP switch.

Clutch Start Switch Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the clutch start switch.
2. Ignition ON, verify a test lamp illuminates between the ignition circuit terminal A and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

3. Verify the scan tool Clutch Start Switch (RPO LE5 and RPO L61) or Clutch Pedal Switch (RPO LSJ) parameter reads Released.

⇒	If not the specified value, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the PCM/ECM.

4. Install a 3A fused jumper wire between the ignition circuit terminal A and the signal circuit terminal B. Verify the scan tool Clutch Start Switch (RPO LE5) or Cluth Pedal Switch (RPO LSJ) parameter reads Applied.

⇒	If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM/ECM.

5. If all circuits test normal, test or replace the Clutch Start Switch.

Crank Relay Circuit Malfunction

1. Ignition OFF, disconnect the CRANK relay.
2. Ignition ON, transmission in Park/Neutral (automatic transmission) or clutch pedal depressed (manual transmission), verify a test lamp illuminates between the relay coil ignition circuit terminal and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

3. Verify a test lamp illuminates between the relay switch B+ circuit terminal and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the CRANK fuse is open, test the relay controlled output circuit for a short to ground.

4. Connect a test lamp between the relay coil ignition circuit terminal and the relay coil control circuit terminal.

Important: The engine may begin to crank.

5. Ignition ON, transmission in Park/Neutral (automatic transmission) or clutch pedal depressed (manual transmission), command the Start Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the PCM/ECM.

⇒	If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the PCM/ECM.

6. Connect the CRANK relay.
7. Install a test lamp between the starter S terminal and ground.

Important: The engine may begin to crank.

8. Ignition ON, transmission in Park/Neutral (automatic transmission) or clutch pedal depressed (manual transmission), command the Start Relay ON with a scan tool. The test lamp should illuminate.

⇒	If the test lamp does not illuminate, test the relay controlled output circuit for an open/high resistance. If the circuit tests normal, test or replace the CRANK relay.

9. If all circuits test normal, test or replace the starter.

PNP Switch

1. Ignition OFF, disconnect the harness connector at the PNP switch.
2. With the PNP switch in the following positions, test for infinite resistance between the ignition terminal 12 and the signal terminal 1.

•

R

•

OD

•

D

•

2

•

1

⇒	If not the specified value, replace the PNP switch.

3. With the PNP switch in the following positions, test for less than 2.0 ohms of resistance between the ignition terminal 12 and the signal terminal 1.

•

P

•

N

⇒	If greater than the specified range, replace the PNP switch.

Clutch Start Switch

1. Ignition OFF, disconnect the harness connector at the clutch start switch.
2. With the switch in the open position, test for infinite resistance between the B+ terminal A and the signal terminal B.

⇒	If not the specified value, replace the clutch start switch.

3. With the switch in the closed position, test for less than 2.0 ohms of resistance between the B+ terminal A and the signal terminal B.

⇒	If greater than the specified range, replace the clutch start switch.

CRANK Relay

1. Ignition OFF, disconnect the CRANK relay.
2. Test for 60-180 ohms of resistance between terminals 85 and 86.

⇒	If not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified value, replace the relay.

4. Install a 20-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2.0 ohms of resistance between terminals 30 and 87.

⇒	If greater than specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.