What Does B1358 Mean?
This code indicates the Body Control Module (BCM) has detected that the ignition run circuit voltage is shorted to ground. The ignition run circuit provides power to various vehicle systems when the ignition switch is in the run position. This short causes the circuit voltage to drop below the expected threshold, preventing proper power distribution to ignition-dependent components.
Safety Warning
Vehicle may not start or may stall unexpectedly while driving due to loss of ignition run power. Do not drive until repaired as this can cause sudden loss of critical systems including fuel pump, ignition coils, and engine management components.
Common Causes
45%
Damaged wiring harness or chafed insulation causing wire-to-ground contact in ignition run circuit
30%
Faulty ignition switch with internal short to ground
15%
Corroded or damaged BCM connector causing ground short
10%
Failed Body Control Module with internal circuit fault
Diagnostic Steps
1
Step 1: Perform visual inspection of ignition switch wiring harness from BCM to ignition switch, looking for chafed, pinched, melted, or damaged wires, especially near sharp edges, moving parts, and heat sources
2
Step 2: Disconnect ignition switch connector and measure resistance between ignition run circuit terminal and chassis ground using digital multimeter (DMM). Reading should be >10k ohms; low resistance confirms short to ground in wiring
3
Step 3: If wiring tests good, disconnect BCM connector and repeat resistance test from BCM side of ignition run circuit to ground. This isolates whether short is in harness or BCM internal circuitry
4
Step 4: With ignition switch disconnected, check ignition switch internal resistance between run terminal and ground terminal per manufacturer specifications using DMM. Replace switch if out-of-spec or shows continuity when it shouldn't
5
Step 5: Inspect BCM connector terminals for corrosion, bent pins, or moisture intrusion that could cause grounding. Clean or repair connector as needed
6
Step 6: After repairs, clear codes, cycle ignition switch through all positions multiple times, and verify ignition run circuit voltage at BCM is within specification (typically 12-14V in run position) with no code return
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected that the ignition run circuit voltage is shorted to ground. The ignition run circuit provides power to various vehicle systems when the ignition switch is in the run position. This short causes the circuit voltage to drop below the expec...
The most common cause of B1358 (Ignition Run Circuit Short To Ground) is: Damaged wiring harness or chafed insulation causing wire-to-ground contact in ignition run circuit
Typical repair costs for B1358 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may not start or may stall unexpectedly while driving due to loss of ignition run power. Do not drive until repaired as this can cause sudden loss of critical systems including fuel pump, ignition coils, and engine management components.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1358 to identify the root cause.
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Quick Info
Category
Body
System
Body Control Module / Ignition Power Distribution
Difficulty
Type
Manufacturer
Recommended Tools
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