What Does B1370 Mean?
B1370 indicates the body control module (BCM) has detected a short to ground condition in the ignition tachometer signal circuit. This code relates to the circuit that carries the tachometer signal from the ignition system or engine control module to the instrument cluster or BCM. The module detected abnormally low resistance or voltage in this circuit, indicating the signal wire is contacting ground somewhere in the wiring harness or at a connection point.
Common Causes
45%
Damaged or chafed wiring in the tachometer signal circuit causing direct contact with vehicle ground
30%
Corroded or moisture-damaged connector terminals at the instrument cluster or BCM
15%
Failed instrument cluster with internal short circuit on tachometer input
10%
Faulty body control module with damaged tachometer input circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of the tachometer signal wire from the engine compartment through the firewall to the instrument cluster, looking for pinched, chafed, or damaged insulation, especially at routing points and connectors
2
Step 2: Disconnect the instrument cluster connector and use a digital multimeter to measure resistance between the tachometer signal wire terminal and known good chassis ground - should read infinite resistance (open circuit); low resistance indicates a short to ground
3
Step 3: If short is detected, disconnect the BCM connector and re-test resistance to ground on the tachometer signal wire - if short disappears, BCM is likely faulty; if short persists, wiring harness is damaged between connectors
4
Step 4: Inspect all connectors for corrosion, moisture intrusion, or pushed-out terminals using a flashlight and magnification; clean contacts with electrical contact cleaner and dielectric grease if corrosion is present
5
Step 5: If wiring harness is damaged, repair the short by cutting out damaged section and soldering in new wire with heat-shrink insulation, ensuring proper routing away from sharp edges
6
Step 6: Clear codes, verify tachometer operation with engine running at various RPMs, and road test to confirm repair; monitor for code recurrence
Estimated Repair Cost
$100 - $650
Parts + labor, varies by vehicle and location
B1370 indicates the body control module (BCM) has detected a short to ground condition in the ignition tachometer signal circuit. This code relates to the circuit that carries the tachometer signal from the ignition system or engine control module to the instrument cluster or BCM. The module detecte...
The most common cause of B1370 (Ignition Tach Circuit Short To Ground) is: Damaged or chafed wiring in the tachometer signal circuit causing direct contact with vehicle ground
Typical repair costs for B1370 range from $100 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This code does not affect vehicle safety or drivability and it is safe to continue driving. The tachometer may not function properly, but all critical vehicle systems remain operational and repair can be scheduled at convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1370 to identify the root cause.
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Quick Info
Category
Body
System
Body Control System / Instrument Cluster
Difficulty
Type
Manufacturer
Recommended Tools
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