Code
P1358
CITROEN
P — Powertrain
Ignition coil 1 short circuit to positive
Views:
UK: 3
EN: 8
RU: 2
AI status
Completed
Completed
100%
Causes
- Damaged ignition coil with internal short to positive
- Wiring or harness chafed and shorted to battery positive
- Corroded/damaged coil connector or terminal contacting B+
- Aftermarket or incorrect replacement coil with internal fault
- Faulty ECM driver stage or internal short inside ECM
- Blown or loose ignition-related fuse or fusible link allowing abnormal voltages
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light ON
- Cylinder 1 misfire, rough idle or reduced power
- Hard starting or no-start in severe cases
- Poor fuel economy and increased emissions
- Intermittent misfire or roughness under load
What to check
- Read freeze-frame and live data; note misfire counters and conditions when code set
- Visual inspection of coil 1, connector and wiring for damage, oil, corrosion or pinched areas
- Check for battery voltage at the coil supply terminal with ignition ON (should be ~11–14 V)
- Disconnect coil 1 connector and check continuity between coil primary and battery positive (should not be a direct short)
- Measure coil primary and secondary resistances and compare to spec
- Swap coil 1 with another cylinder's coil and see if fault/code follows the coil
Signal parameters
- Battery voltage at coil supply (key ON): ~11–14 V
- Coil primary resistance (typical): ~0.3–2.0 Ω (verify vehicle spec)
- Coil secondary resistance (typical): ~5 kΩ–25 kΩ (verify vehicle spec)
- ECM driver: low-side switching to ground (should see pulsed ground when cranking/running)
- Continuity between coil primary and B+ when connector unplugged: should be open/high resistance (no direct short)
Diagnostic algorithm
- Retrieve stored data (freeze frame, misfire counters) and note conditions when code set.
- Perform a visual inspection of coil 1, its connector and wiring loom for heat damage, chafing, corrosion or oil contamination. Repair visible damage.
- With ignition OFF, disconnect coil 1. Measure primary and secondary coil resistance and compare to manufacturer specs. Replace coil if out of spec.
- With coil unplugged, check continuity between the coil's primary terminal and battery positive. There should be no direct short. If continuity present, trace wiring to find short to B+ and repair.
- With ignition ON (engine off), backprobe the coil connector: confirm battery voltage at the B+ feed and no unexpected constant B+ on the driver pin. The driver pin should not be permanently at battery voltage.
- Reconnect coil 1 and observe ECM driver behavior (oscilloscope preferred): verify the driver is switching to ground. If driver is stuck high or shows short to B+, suspect wiring or ECM.
- Swap coil 1 with another cylinder’s coil. If the code follows the coil, replace the coil. If the code stays on cylinder 1, focus on wiring/ECM for that circuit.
- Inspect and test related fuses/fusible links and repair any faults.
- If wiring and coil check good but short persists, consult manufacturer guidance—ECM driver may be faulty and require replacement or specialist testing.
- After repair, clear codes and test drive to confirm the code does not return and misfire condition is resolved.
Likely causes
- Faulty ignition coil 1 (most common)
- Shorted or pinched wiring between coil connector and fuse/ignition feed
- Contaminated/corroded connector creating unintended B+ path
- Failed driver in ECM (less common; suspect after wiring and coil verified)
Fault status
Status
Check Engine light ON — Ignition coil 1 short to positive (P1358). Possible misfire, rough idle or no-start. Inspect coil, wiring and connector.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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