• Perform the Diagnostic System Check prior to using this diagnostic procedure:Diagnostic System Check - Vehicle
• Review the description of Strategy Based Diagnosis:Strategy Based Diagnosis
• An overview of each diagnostic category can be found here:Diagnostic Procedure Instructions

There are 2 ignition voltage circuits supplied to the ECM. The 2 circuits are supplied by 1 relay(s):KR75 Engine Controls Ignition Relay

The ECM monitors and compares the voltages supplied by the relay(s).

• Ignition Voltage=Greater than 11 V

Frequency the DTC runs=Continuously—After the running conditions are met

• Ignition Voltage=Greater than 9 V
• Engine Controls Ignition Relay Command=On

Frequency the DTC runs=Continuously—After the running conditions are met

• DTC P0685 = Not set
• Engine Controls Ignition Relay Command=Off—For greater than 2 s

Frequency the DTC runs=Continuously—After the running conditions are met

• Engine Controls Ignition Relay Command=On
• Ignition Voltage=Greater than 5.5 V

Frequency the DTC runs=Continuously—After the running conditions are met

Control Circuit=Commanded state does not match the actual state—Greater than 2 s

Engine Controls Ignition Relay Feedback Signal=Commanded state does not match the actual state—Greater than 5 s

Engine Controls Ignition Relay Feedback Signal=Commanded state does not match the actual state—Greater than 5 s

The following parameters are not within 3 V of each other:

• Ignition 1 Signal
• Engine Controls Ignition Relay Feedback Signal
• Engine Controls Ignition Relay Feedback 2 Signal

DTCs listed in the DTC Descriptor category=Type B DTC—Exceptions listed below

DTC P0689, P16AF=Type C DTC

DTC P1682=Type A DTC

DTCs listed in the DTC Descriptor category=Type B DTC—Exceptions listed below

DTC P0689, P16AF=Type C DTC

DTC P1682=Type A DTC

If the condition is intermittent, wiggle the related wiring harnesses and connectors, with the ignition/vehicle on or engine running, while monitoring the scan tool circuit status parameters for the component. The parameters will display if there is a condition with the circuit or a connection.

• Engine Controls Schematics
• Power Distribution Schematics

Master Electrical Component List

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

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Control Module References

1. Ignition » On / Vehicle » In Service Mode
2. Verify no other DTCs are set.
• If other DTCs are set

  Refer to:Diagnostic Trouble Code (DTC) List - Vehicle

• If no other DTCs are set
3. Ignition»Cycle Off and On&Cycle On and Off

   Verify a click can be heard or felt at the following component(s) when the scan tool control function was commanded:KR75 Engine Controls Ignition Relay

• If a click cannot be heard or felt

  Refer to: Circuit/System Testing

• If a click can be heard or felt
4. Verify the following parameters are within 3 V of each other:
• Ignition 1 Signal
• Engine Controls Ignition Relay Feedback Signal
• If not within 3 V of each other

  Refer to: Circuit/System Testing

• If within 3 V of each other
5. 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.

   Verify the DTC does not set.

• If the DTC sets

  Refer to: Circuit/System Testing

• If the DTC does not set
6. All OK.

1. Ignition/Vehicle » Off
2. Remove the component:KR75 Engine Controls Ignition Relay
3. Verify a test lamp turns On between the test points:
• B+ circuit terminal 3&Ground
• B+ circuit terminal 1&Ground
• If the test lamp does not turn On

  Replace the component:X50A Fuse Block - Underhood

• If the test lamp turns On
4. Ignition » On / Vehicle » In Service Mode
5. Connect a test lamp between the test points:B+ circuit terminal 1&Control circuit terminal 2
6. Perform the scan tool control function:Engine Controls Ignition Relay»On and Off

   Verify the test lamp turns On and Off.

• If the test lamp is always Off
1. Ignition/Vehicle » Off & Remove » Test lamp
2. Disconnect the appropriate electrical connector:K20 Engine Control Module
3. Ignition » On / Vehicle » In Service Mode
4. Test for less than 1 V between the test points:Control circuit terminal 2@Relay Socket&Ground
• If 1 V or greater » Repair the short to voltage on the circuit.
• If less than 1 V
5. Ignition/Vehicle » Off
6. Test for less than 2 Ω between the test points:Control circuit terminal 2@Relay Socket&The other end of the circuit@Control module harness
• If 2 Ω or greater » Repair the open/high resistance in the circuit.
• If less than 2 Ω » Replace the component:K20 Engine Control Module
• If the test lamp is always On
1. Ignition/Vehicle » Off & Remove » Test lamp
2. Disconnect the appropriate electrical connector:K20 Engine Control Module
3. Test for infinite resistance between the test points:Control circuit terminal 2@Relay Socket&Ground
• If less than infinite resistance » Repair the short to ground on the circuit.
• If infinite resistance » Replace the component:K20 Engine Control Module
• If the test lamp turns On and Off
7. Verify the fuse is not open:F4UA, F17UA Fuse—For the circuit that set the DTC.
• If the fuse is open
1. Ignition/Vehicle & All vehicle systems » Off
2. Disconnect the appropriate electrical connector:K20 Engine Control Module
3. Test for infinite resistance between the test points:Output terminal@Fuse&Ground
• If less than infinite resistance » Repair the short to ground on the circuit.
• If infinite resistance » Replace the component:K20 Engine Control Module
• If the fuse is not open
8. Ignition » On / Vehicle » In Service Mode
9. Verify a test lamp does not turn On between the test points:Ignition circuit terminal 5@Relay Socket&Ground
• If the test lamp turns On
10. Ignition/Vehicle & All vehicle systems » Off
11. Disconnect the appropriate electrical connector:K20 Engine Control Module
12. Test for less than 1 V between the test points:Ignition circuit terminal 16 X1, 73 X1@Control module harness&Ground
• If 1 V or greater » Repair the short to voltage on the circuit.
• If the test lamp does not turn On
13. Ignition/Vehicle » Off

Caution: Complete the testing as quickly as possible in order to prevent overheating and damaging the component.

14. Connect a 30 A fused jumper wire between the test points:Ignition circuit terminal 5&B+ circuit terminal 3
15. Ignition » On / Vehicle » In Service Mode
16. Verify the scan tool parameter:Engine Controls Ignition Relay Feedback Signal=Within 1 V of the battery voltage
• If not within 1 V of the battery voltage
1. Ignition/Vehicle » Off & Remove » Jumper wire(s)
2. Disconnect the appropriate electrical connector:K20 Engine Control Module
3. Test for less than 2 Ω between the test points:Ignition circuit terminal 5@Relay Socket&Ignition circuit terminal 16 X1, 73 X1@Control module harness
• If 2 Ω or greater » Repair the open/high resistance in the circuit.
• If less than 2 Ω » Replace the component:K20 Engine Control Module
• If within 1 V of the battery voltage
17. Test or replace the component:KR75 Engine Controls Ignition Relay

1. Ignition/Vehicle » Off
2. Remove the component:KR75 Engine Controls Ignition Relay
3. Test for 70 to 110 Ω between the test points:Component terminal 2&1
• If not between 70 and 110 Ω

  Replace the component:KR75 Engine Controls Ignition Relay

• If between 70 and 110 Ω
4. Test for infinite resistance between the test points:
• Component terminal 3&2
• Component terminal 3&1
• Component terminal 3&5
• Component terminal 2&5
• If less than infinite resistance

  Replace the component:KR75 Engine Controls Ignition Relay

• If infinite resistance
5. Connect a 3 A fused jumper wire between the test points:Component terminal 1&B+

   Connect a jumper wire between the test points:Component terminal 2&Ground

6. Test for less than 2 Ω between the test points:Component terminal 3&5
• If 2 Ω or greater

  Replace the component:KR75 Engine Controls Ignition Relay

• If less than 2 Ω
7. All OK.

Perform the Diagnostic Repair Verification after completing the repair:Diagnostic Repair Verification

• Engine Wiring Harness Junction Block Replacement
• Electrical Relay Replacement
• For control module replacement, programming, and setup refer to:Control Module References