Diagnostic Test
- TEST FOR INTERMITTENT CONDITION NOTE: Open the hood and ensure the Hood Ajar Switch is connected before proceeding
- With the scan tool, record and erase DTCs.
- Close the hood.
- Cycle the ignition from on to off.
- Turn the ignition on.
- Open then close the hood.
- With the scan tool, read DTCs.
Does the scan tool display B1820-HOOD AJAR INPUT CIRCUIT HIGH?
Yes
- Go to step 2
No
- The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure
- INCORRECT HOOD AJAR SWITCH INSTALLED
- Inspect the retainer ring on the hood ajar switch.
- A dark brown retainer ring identifies the hood ajar switch used for certain export applications, while a white retainer ring identifies the remote starter system application.
Is the correct switch installed?
Yes
- Go to step 3
No
- Replace the Hood Ajar Switch.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure
- HOOD AJAR SWITCH OPEN
- Disconnect the Hood Ajar Switch harness connector.
- Depress the plunger of the hood ajar switch and measure the resistance between the two terminals of the switch.
Is the resistance approximately 1k ohms?
Yes
- Go to step 4
No
- Replace the Hood Ajar Switch.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure
- (Z926) GROUND CIRCUIT OPEN
- Using a 12-volt Test Light connected to 12-volts, check the (Z926) Ground circuit.
Does the test light illuminate?
Yes
- Go to step 5
No
- Repair the (Z926) Ground circuit for an open.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure
- Using a 12-volt Test Light connected to 12-volts, check the (Z926) Ground circuit.
- (G70) HOOD AJAR SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
- Disconnect the FCM 49-way connector.
- Turn the ignition on.
- Measure the voltage between the (G70) Hood Ajar Switch Sense circuit and ground.
Is there any voltage present?
Yes
- Repair the (G70) Hood Ajar Switch Sense circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure
No
- Go to step 6
- (G70) HOOD AJAR SWITCH SENSE CIRCUIT OPEN
- Turn the ignition off.
- Measure the resistance of the (G70) Hood Ajar Switch Sense circuit between the FCM 49-way connector and the Hood Ajar Switch connector.
Is the resistance below 2.0 ohms?
Yes
- Replace the Front Control Module (FCM) in accordance with the Service Information.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure
No
- Repair the (G70) Hood Ajar Switch Sense circuit for an open.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure