What Does B1368 Mean?
B1368 indicates the Body Control Module (BCM) has detected an open circuit in the ignition tachometer signal circuit. This circuit carries the engine RPM signal from the ignition system or ECM to the instrument cluster tachometer and possibly other modules. An open circuit means the electrical path is broken, preventing the tachometer signal from being transmitted properly, which may result in a non-functional tachometer gauge and potential issues with modules that rely on RPM data.
Common Causes
45%
Broken, corroded, or disconnected wiring in the tachometer signal circuit between the ignition module/ECM and instrument cluster
25%
Faulty instrument cluster with internal open circuit on tachometer input
20%
Failed ignition control module or coil pack not generating tachometer reference signal
10%
Damaged or corroded BCM connector pins at the tachometer signal input terminal
Diagnostic Steps
1
Step 1: Perform a visual inspection of the instrument cluster connector and BCM connectors for bent pins, corrosion, or loose connections. Check for damaged wiring harness between the ignition module and instrument cluster.
2
Step 2: Using a digital multimeter in AC voltage mode, backprobe the tachometer signal wire at the instrument cluster connector while engine is running. Expected reading should show pulsing AC voltage (typically 5-12V AC) that varies with engine RPM. No voltage indicates open circuit upstream.
3
Step 3: If no signal is present at the cluster, trace the tachometer signal wire back toward the ignition module/ECM and test at intermediate connectors to isolate the location of the open circuit. Check for continuity between BCM and ignition module with engine off and connectors disconnected.
4
Step 4: If continuity is good throughout the circuit, test the ignition module or coil pack tachometer output terminal with engine running to verify signal generation. If no signal is present at the source, replace the ignition module or coil pack.
5
Step 5: If signal is present at the instrument cluster connector but code persists, suspect internal cluster failure. Consider cluster replacement or professional repair of circuit board.
6
Step 6: After repair, clear codes, perform multiple engine start cycles and drive at varying RPMs, then verify tachometer operation and confirm code does not return.
Estimated Repair Cost
$75 - $650
Parts + labor, varies by vehicle and location
B1368 indicates the Body Control Module (BCM) has detected an open circuit in the ignition tachometer signal circuit. This circuit carries the engine RPM signal from the ignition system or ECM to the instrument cluster tachometer and possibly other modules. An open circuit means the electrical path ...
The most common cause of B1368 (Ignition Tach Circuit Open) is: Broken, corroded, or disconnected wiring in the tachometer signal circuit between the ignition module/ECM and instrument cluster
Typical repair costs for B1368 range from $75 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving. The primary impact is loss of tachometer function on the instrument cluster, which may make it difficult to monitor engine RPM but does not affect vehicle operation or safety. Repair at convenience unless other modules require this signal for proper function.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1368 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Instrument Cluster
Difficulty
Type
Manufacturer
Recommended Tools
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