B1370: Ignition Tach Circuit Short To Ground

Definition

The OBD2 code B1370 indicates a fault in the ignition tach circuit, specifically a short to ground, which means there is an unintended connection that allows electrical current to flow directly to the ground, potentially disrupting the normal operation of the ignition system

Common causes

Damaged wiring or connectors in the ignition tach circuit
Short circuit in the ignition tach signal wire
Faulty ignition coil or ignition module
Defective tachometer or instrument cluster
Grounding issues in the electrical system
Corroded or loose connections in the circuit

Common misdiagnoses

Faulty ignition coil
Bad spark plugs
Defective crankshaft position sensor
Malfunctioning camshaft position sensor
Wiring issues or shorts in the harness
Faulty engine control module (ECM)
Incorrectly installed aftermarket components
Battery or charging system problems

Troubleshooting steps

1. Check the Vehicle's Manual

Refer to the vehicle's service manual for specific information about the ignition tach circuit and wiring diagrams
2. Visual Inspection
3. Inspect the wiring and connectors associated with the ignition tach circuit for any signs of damage, fraying, or corrosion
4. Look for any loose connections or broken wires that could cause a short to ground
5. Check for Shorts
6. Use a multimeter to check for continuity in the ignition tach circuit. Disconnect the battery and then check for continuity between the circuit and ground. If there is continuity, there is likely a short to ground
7. Inspect the circuit for any pinched or chafed wires that may be making contact with the vehicle's chassis
8. Test the Ignition Coil and Sensors
9. If the ignition tach circuit is related to the ignition coil or crankshaft position sensor, test these components for proper operation. A faulty ignition coil or sensor can cause issues in the tach circuit
10. Use a multimeter to check the resistance and voltage output of these components according to the specifications in the service manual
11. Check the PCM (Powertrain Control Module)
12. Inspect the PCM for any signs of damage or corrosion. A malfunctioning PCM can also cause issues with the ignition tach circuit
13. If possible, perform a software update or reset the PCM to see if that resolves the issue
14. Scan for Additional Codes
15. Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues
16. Repair or Replace Faulty Components
17. Based on your findings, repair any damaged wiring or connectors. Replace any faulty ignition coils, sensors, or the PCM if necessary
18. Clear the Codes and Test Drive
19. After making repairs, clear the trouble codes using an OBD-II scanner and take the vehicle for a test drive to see if the code returns
20. Seek Professional Help
21. If you are unable to identify or resolve the issue, consider seeking help from a professional mechanic or automotive technician who has experience with electrical systems. By following these steps, you should be able to diagnose and address the issue related to the B1370 code effectively

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check the Vehicle's Manual

2. Visual Inspection

3. Inspect the wiring and connectors associated with the ignition tach circuit for any signs of damage, fraying, or corrosion

4. Look for any loose connections or broken wires that could cause a short to ground

5. Check for Shorts

6. Use a multimeter to check for continuity in the ignition tach circuit. Disconnect the battery and then check for continuity between the circuit and ground. If there is continuity, there is likely a short to ground

7. Inspect the circuit for any pinched or chafed wires that may be making contact with the vehicle's chassis

8. Test the Ignition Coil and Sensors

9. If the ignition tach circuit is related to the ignition coil or crankshaft position sensor, test these components for proper operation. A faulty ignition coil or sensor can cause issues in the tach circuit

10. Use a multimeter to check the resistance and voltage output of these components according to the specifications in the service manual

11. Check the PCM (Powertrain Control Module)

12. Inspect the PCM for any signs of damage or corrosion. A malfunctioning PCM can also cause issues with the ignition tach circuit

13. If possible, perform a software update or reset the PCM to see if that resolves the issue

14. Scan for Additional Codes

15. Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues

16. Repair or Replace Faulty Components

17. Based on your findings, repair any damaged wiring or connectors. Replace any faulty ignition coils, sensors, or the PCM if necessary

18. Clear the Codes and Test Drive

19. After making repairs, clear the trouble codes using an OBD-II scanner and take the vehicle for a test drive to see if the code returns

20. Seek Professional Help

21. If you are unable to identify or resolve the issue, consider seeking help from a professional mechanic or automotive technician who has experience with electrical systems. By following these steps, you should be able to diagnose and address the issue related to the B1370 code effectively