Displays and Gauges
DTC B1370
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B1370 01
- Control Module Ignition On and Start Circuit Short to Battery
DTC B1370 06
- Control Module Ignition On and Start Circuit Open
Diagnostic Fault Information
Circuit/System Description
The vehicle power mode master is the body control module (BCM). The ignition switch is a low current switch with multiple discrete circuits to the BCM.
The power mode master will activate relays and other direct outputs of the power mode master as needed according to the calculated power mode. Some relays controlled by the BCM are switched ignition voltage outputs that are pass through circuits within the BCM directly from the ignition switch. If these circuits short to ground, the B+ circuit fuse to the ignition switch will open.
Conditions for Running the DTC
B1370 01
Ignition switch is in the Accessory position.
B1370 06
Ignition switch is in the Accessory, Run, or Crank positions.
Conditions for Setting the DTC
B1370 01
Ignition circuit is shorted to voltage.
B1370 06
* Ignition circuit is open.
* Ignition or run/crank relay circuit is shorted to ground.
* B+ circuit of the ignition run/crank relay is open or shorted to ground.
* Ignition run/crank relay control circuit open, including relay coil and ground.
Action Taken When the DTC Sets
The Instrument Cluster still functions except check engine light is always off.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.
Reference Information
Schematic Reference
* Instrument Cluster Schematics Instrument Cluster Schematics
* Power Distribution Schematics Power Distribution Schematics
* Power Moding Schematics Power Moding Schematics
Connector End View Reference
Component Connector End Views Outside Rearview Mirror - Driver
Description and Operation
* Instrument Cluster Description and Operation Instrument Cluster
* Power Mode Description and Operation Power Mode
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Verify that DTC B144B or B1380 is not set.
• If DTC B144B or B1380 is set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
• If DTC B144B or B1380 is not set
Refer to Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF, disconnect the KR73 Ignition Main Relay.
2. Test for less than 10 ohms between the ground circuit terminal 1 and ground.
• If 10 ohms or greater
Test the ground circuit for an open/high resistance.
• If less than 10 ohms
3. Verify that a test lamp illuminates between the B+ circuit terminal 3 and ground.
• If the test lamp does not illuminate
Repair the open/high resistance in the circuit.
• If the test lamp illuminates
4. Verify that a test lamp does not illuminate between the control circuit terminal 2 and ground.
• If the test lamp illuminates
1. Disconnect the harness connector at the K9 Body Control Module.
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 K9 Body Control Module.
• If the test lamp does not illuminate
5. Ignition ON, verify that a test lamp illuminates between the control circuit terminal 2 and ground.
• If the test lamp does not illuminate
1. Test for less than 2 ohms in the control circuit end to end.
• If less than 2 ohms, replace the K9 Body Control Module.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If the test lamp illuminates
6. Ignition OFF, reconnect the KR73 Ignition Main Relay.
7. Disconnect the harness connector at the P16 Instrument Cluster.
8. Verify that a test lamp does not illuminate between the ignition circuit terminal 31 and ground.
• If the test lamp illuminates
1. Test for less than 1 V between the ignition circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the KR73 Ignition Main Relay.
• If the test lamp does not illuminate
9. Ignition ON, verify that a test lamp illuminates between the ignition terminal 31 and ground.
• If the test lamp does not illuminate and the Ignition fuse is good
1. Test for less than 2 ohms in the ignition circuit end to end
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the KR73 Ignition Main Relay.
• If the test lamp does not illuminate and the Ignition fuse is open
1. Test for infinite resistance between the ignition circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the P16 instrument cluster.
• If the test lamp illuminates
10. Replace the P16 instrument cluster.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Instrument Cluster Replacement Service and Repair
* Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)
* Control Module References Control Module References for BCM replacement, programming and setup