DIAGNOSIS AND TESTING
B1820-HOOD AJAR INPUT CIRCUIT HIGH
For a complete wiring diagram Refer to Section 8W
- When Monitored:
Continuously
- Set Condition:
When the FCM senses 12 volts on the Hood Ajar Switch Sense circuit for over 10 seconds, this code will set.
| Possible Causes |
| INCORRECT HOOD AJAR SWITCH INSTALLED |
| HOOD AJAR SWITCH OPEN |
| (Z384) GROUND CIRCUIT OPEN |
| (G70) HOOD AJAR SWITCH SENSE CIRCUIT SHORT TO VOLTAGE |
| (G70) HOOD AJAR SWITCH SENSE CIRCUIT OPEN |
| FRONT CONTROL MODULE (FCM) |
Diagnostic Test
1. TEST FOR INTERMITTENT CONDITIONNOTE: Open the hood and ensure the Hood Ajar Switch is connected before proceeding
With the scan tool, record and erase DTC's
Close the hood.
Cycle the ignition from on to off. Turn the ignition on.
Open then close the hood.
With the scan tool, read DTC's.
Does the scan tool display B1820–HOOD AJAR INPUT CIRCUIT HIGH?
Yes
- Go To 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 BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
2. 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 3
No
- Replace the Hood Ajar Switch.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
3. HOOD AJAR SWITCH OPEN
Disconnect the Hood Ajar Switch harness connector.
Measure the resistance between the two terminals of the Hood Ajar Switch
Is the resistance approximately 1000 ohms?
Yes
- Go To 4
No
- Replace the Hood Ajar Switch.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
4. (Z384) GROUND CIRCUIT OPEN
Using a 12-volt Test Light connected to 12-volts, check the (Z384) Ground circuit.
Does the test light illuminate?
Yes
- Go To 5
No
- Repair the (Z384) Ground circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
5. (G70) HOOD AJAR SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
Disconnect the Front Control Module 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 BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
No
- Go To 6
6. (G70) HOOD AJAR SWITCH SENSE CIRCUIT OPEN
Turn the ignition off.
Disconnect the Integrated Power Module C2 40–way connector.
Measure the resistance of the (G70) Hood Ajar Switch Sense circuit between the IPM connector and the Hood Ajar Switch connector.
Is the resistance below 2.0 ohms?
Yes
- Go To 7
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
No
- Repair the (G70) Hood Ajar Switch Sense circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
7. (G70) IPM HOOD AJAR SWITCH SENSE CIRCUIT OPEN
Use the graphic as a reference to check the Integrated Power Module .
Measure the resistance of the (G70) Hood Ajar Switch Sense circuit between the IPM C2 40–connector and the Front Control Module 49–way connector.
Is the resistance below 1.0 ohms?
Yes
- Replace the Front Control Module (FCM) in accordance with the service information.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
No
- Replace the Integrated Power Module (IPM) in accordance with the service information.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)