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Home / Diagnostic Decoder / Powertrain System / Code P1351
System: Powertrain (P-Code) Coverage: OEM Specific (GMC) Fault Family: ignition_coil_control_circuit

Code P1351: IC Circuit High Voltage

Diagnostic & Technical Explanation
Code P1351 (IC Circuit High Voltage) sets when the ECM (or, on coil-on-plug systems with many cylinders, a dedicated ignition driver) detects an open circuit or out-of-range voltage while commanding a specific coil's primary winding, covering both the classic per-letter Ignition Coil Primary Control Circuit/Open codes and the newer Ignition [Letter] Control Signal Circuit Open/Low/High variants used on high-cylinder-count and coil-per-plug platforms. In every variant the physical fault sits in the same place: a failed coil primary winding, a corroded or unseated coil connector, or chafed wiring between the ECM/driver and that specific coil.

Probability-Ranked Repair Procedures (4 Ranked Fixes)

Rank #1

Inspect and reseat the ignition coil connector

Easy DIY
Parts Estimate: $5.0–$15.0 USD Labor Estimate: 0.3 Shop Hours
  1. 1. Unplug the connector for the affected coil letter/cylinder
  2. 2. Inspect pins for corrosion, heat damage, or a bent terminal
  3. 3. Clean contacts with electrical contact cleaner and reseat fully
  4. 4. Clear the code and re-test under load
Required Replacement Parts: 🔧 Electrical contact cleaner
Rank #2

Replace the ignition coil

Moderate DIY
Parts Estimate: $25.0–$120.0 USD Labor Estimate: 0.4 Shop Hours
  1. 1. Remove the engine cover and any coil retaining bolts
  2. 2. Disconnect the harness and pull the coil from its plug well
  3. 3. Install the replacement coil and torque the retaining bolt to spec
  4. 4. Reconnect, clear the code, and verify no misfire returns
Required Replacement Parts: 🔧 Ignition coil-on-plug unit · 🔧 Coil boot/seal kit
Rank #3

Repair coil driver wiring back to the ECM/ignition module

Professional Required
Parts Estimate: $10.0–$70.0 USD Labor Estimate: 1.4 Shop Hours
  1. 1. Measure coil primary resistance at the connector against spec
  2. 2. Voltage-drop test the driver, ground, and reference legs to the ECM or ignition control module
  3. 3. Repair chafed or corroded conductors with soldered, heat-shrunk splices
  4. 4. Clear codes and confirm clean coil-on/coil-off waveforms with a scope
Required Replacement Parts: 🔧 Automotive wiring repair kit (solder + heat-shrink)
Rank #4

Replace a failed ignition control/driver module

Professional Required
Parts Estimate: $80.0–$400.0 USD Labor Estimate: 2.0 Shop Hours
  1. 1. Confirm coil and wiring test good but the driver circuit still faults
  2. 2. Locate the ignition control module or driver stage (stand-alone or integrated in the ECM)
  3. 3. Replace the module and reprogram/relearn as required
  4. 4. Clear codes and verify all coil channels fire correctly
Required Replacement Parts: 🔧 Ignition control module

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