Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / P1356 — IC Output High/Pulse Detected When Grounded Cyl.6

P1356 — IC Output High/Pulse Detected When Grounded Cyl.6

Detailed page for trouble code P1356.

34,664codes
59brands
11,925generic
22,739specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

P1356

CHEVROLET P — Powertrain

IC Output High/Pulse Detected When Grounded Cyl.6

Brand: CHEVROLET
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Short to battery voltage or backfeed on the coil primary or driver circuit
  • Internal short or failure in the ignition coil/module for cylinder 6
  • Damaged, chafed, or corroded wiring or connector at the coil driver
  • Poor or missing ground at the coil or ECM/PCM
  • Faulty ECM/PCM ignition driver transistor
  • Aftermarket components or incorrect replacement parts

Symptoms

  • Check Engine Light (MIL) illuminated
  • Misfire or rough running, often referenced to cylinder 6
  • Poor idle quality and reduced power
  • Decreased fuel economy
  • Possible hard starting or intermittent no-start (if driver fails)

What to check

  • Read and record freeze frame data and any additional DTCs; note engine RPM, battery voltage and operating conditions
  • Visually inspect coil pack, connector and wiring for cylinder 6 for damage, corrosion, loose pins or evidence of arcing
  • Verify related codes (P0356 and other coil/circuit codes for other cylinders)
  • Use a scan tool to command/coerce coil operation (if available) and observe behavior
  • Measure continuity and resistance of coil primary and secondary circuits (compare with spec or known-good coil)
  • Probe the coil primary/driver circuit with a digital scope while cranking and running to observe actual voltage waveform

Signal parameters

  • Normal off-state voltage at coil primary/driver: near battery voltage (approx. 12–14 V)
  • Normal on-state (driver grounding) measured at coil primary: near 0 V (ground) while firing
  • Primary pulse width (dwell) varies with RPM — typically a few milliseconds at idle, increasing with load/RPM
  • Firing frequency corresponds to engine speed and number of ignition events per engine cycle for that cylinder
  • A persistent voltage or pulse on the driver when PCM commands ground indicates a short/backfeed or driver fault

Diagnostic algorithm

  1. Connect a scanner, retrieve the freeze frame and live data. Confirm P1356 and note any associated misfire or coil codes.
  2. Perform a careful visual inspection of the coil pack, harness and connector for cylinder 6. Repair any obvious damage before further testing.
  3. Clear the code and attempt to reproduce. If intermittent, wiggle-test the harness and connector while monitoring for code return.
  4. Swap the coil pack (or coil module) from cylinder 6 with a known-good cylinder. If the code moves to the other cylinder, suspect the coil; if it stays on #6, suspect wiring/PCM.
  5. With ignition ON (engine off) and/or while cranking, measure voltage at the coil primary terminal: verify battery voltage when driver is off and near 0 V when PCM grounds the driver. Use an oscilloscope for live-running waveform analysis to detect unexpected pulses or backfeed.
  6. Check continuity to battery power and ground for the coil circuit. Look for shorts to power on the driver control side or to other circuits.
  7. Inspect and test connector pins for corrosion or poor contact. Repair/replace any damaged connectors or harness sections; protect repaired wiring from chafing and moisture.
  8. If wiring and coil test good but pulse/high persists when driver should be grounded, consider replacing the ECM/PCM driver or the entire PCM only after all other causes eliminated.
  9. After repairs, clear codes and perform a road test under the same conditions captured in freeze frame to verify the fault is resolved.
  10. Safety: isolate battery power before performing connector repairs. When probing live ignition circuits use appropriate insulated tools and follow OEM safety guidelines.

Likely causes

  • Shorted coil primary winding causing backfeed into the driver circuit
  • Damaged wiring harness where the coil feed is rubbing and contacting battery voltage
  • Corroded/loose connector on coil pack allowing intermittent voltage/pulse
  • Failed ignition coil pack or module on cylinder 6
  • ECM/PCM driver damaged from previous short or moisture

Fault status

⚠️ Status
Ignition control output for cylinder 6 detected high/pulse when expected to be grounded; possible short, coil or driver fault.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours
528

Browse 528 CHEVROLET manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

CHEVROLET

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .