B1357

Code

Other B — Body

Ignition Run Circuit Short To Battery

Brand: Other

Type: B — Body

Views: UK: 26 EN: 29 RU: 26

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged insulation allowing ignition RUN wire to contact battery positive or a constant B+ feed
Corroded or pushed‑back connector pins creating unintended B+ contact
Stuck/failed ignition relay or relay contacts welded closed
Faulty ignition switch or ignition switch internal short
Aftermarket alarm/remote start or improper accessory wiring tied to ignition RUN
Faulty body control module (BCM)/instrument cluster internal short

Symptoms

Ignition ON/RUN circuits powered when key is OFF
Engine may continue running after key OFF or accessories stay powered
Parasitic battery drain or battery not charging down normally
Malfunction indicator lamp or body module faults stored
Starter behavior may be abnormal or vehicle may not go to expected key-off states

What to check

Retrieve all stored codes and freeze frame data with a scan tool
Visually inspect wiring harnesses and connectors along ignition RUN circuit for damage, chafe, corrosion, or aftermarket splices
Check for aftermarket alarm/remote start modules and their wiring ties to ignition circuits
Backprobe ignition RUN circuit at ignition switch and BCM with ignition OFF and RUN positions to monitor voltage
Check ignition/run relay operation and remove or swap relay to test
Measure parasitic draw with both key OFF and after vehicle sleeps

Signal parameters

Ignition RUN wire voltage with key OFF: ~0.0–0.5 V (should be low)
Ignition RUN wire voltage with key RUN/ON: battery voltage ~11.5–14.5 V
Voltage transition from OFF→RUN should be a clean change to battery voltage when key turned on (no constant battery when OFF)
Parasitic current when key OFF: typically

Diagnostic algorithm

Use a scan tool: record B1357 plus any related codes and freeze frame data; note ignition state when set.
Visually inspect ignition switch area, harness, BCM connectors and any aftermarket devices for obvious damage, tape splices, or loose pins.
With vehicle OFF and key removed, measure continuity between ignition RUN circuit and battery positive (B+) with a multimeter. Expected: open. If continuity present, circuit is shorted to B+.
With backprobe or fused test light, monitor RUN circuit voltage while moving harness and connectors to see if voltage appears (helps locate chafe/short).
Remove/disable ignition RUN relay or unplug relay socket (if applicable) and recheck RUN circuit voltage — if voltage drops, suspect relay or feed to relay.
Isolate by disconnecting connectors along the circuit (ignition switch, BCM, fuse box) one at a time until the short clears; the last connector removed that clears the short locates the section with fault.
Inspect and repair any damaged wires, replace corroded connectors, repair pin recesses, or reroute and protect chafed wiring.
If wiring and connectors check good, bench‑test or substitute suspected modules (ignition switch, BCM) per manufacturer procedures before replacing; do not replace modules without isolating fault.
After repair, clear codes, verify proper RUN circuit voltages in OFF/RUN positions, confirm no parasitic draw, and road/test to ensure code does not return.

Likely causes

Wiring chafe or pinched harness contacting battery feed or constant B+ circuit
Connector corrosion or bent pins at ignition switch or BCM
Aftermarket remote start or alarm wiring tied to constant B+ instead of switched feed
Failed ignition/run relay (contacts welded closed)

Fault status

⚠️ Status

Ignition RUN circuit is reporting a short to battery voltage (B+). The body/control module detected constant battery feed where a switched/controlled signal was expected. Inspect wiring, connectors, relays, and aftermarket additions before replacing modules.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours