P1364 Ignition Coil D Primary Circuit Malfunction
The P1364 code indicates a malfunction in the primary circuit of ignition coil D. This circuit includes the low-voltage wiring from the ECM/PCM to the coil and the internal switching transistor. The code sets when the ECM detects an abnormal voltage, current, or response from coil D's control circuit, typically corresponding to cylinder 4 in V6/V8 engines, though it may vary by firing order. Detection is usually via a feedback circuit (IGF) or by monitoring expected current during the ignition event.
01. Most Common Causes
- Faulty ignition coil D (open or shorted primary circuit)
- Damaged, corroded, or poorly connected wiring between ECM and coil D
- Bent, corroded, or loose pins in the ignition coil connector
- Internal ECM failure (damaged coil control transistor)
- Excessive resistance in the coil ground circuit
- Blown or high-resistance ignition circuit fuse (if applicable)
02. Symptoms You Will Notice
- Engine misfire on cylinder 4 (or corresponding cylinder)
- Check Engine Light illuminated
- Rough idle, hesitation, or loss of power
- Possible hard starting or no-start condition
03. Step-by-Step Diagnosis
Scan for codes and verify P1364 is present; check for related misfire codes.
Inspect ignition coil D connector for corrosion, damage, or loose pins.
Test coil D primary resistance with a multimeter (specs vary by vehicle).
Check for battery voltage and ground at coil D connector with key on.
Perform a power balance test to isolate the misfiring cylinder.
If wiring and coil check out, test ECM output with a lab scope or substitute a known-good coil.
1. Frequently Asked Questions
Is it safe to drive?▼
Driving with P1364 is not recommended as it can cause engine misfire, reduced performance, and potential damage to the catalytic converter. Have the vehicle diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on whether the coil, wiring, or ECM needs replacement. Diagnostic fees are extra.