Cylinder 9 Glow Plug Control Circuit High
The P069B code indicates that the powertrain control module (PCM) has detected a high voltage condition in the glow plug control circuit for cylinder 9. This circuit includes the glow plug, wiring, connector, and the glow plug control module. A high voltage reading typically suggests a short to voltage, a faulty glow plug control module, or an open circuit. This code is common in diesel engines with multiple glow plugs, especially in larger trucks or vehicles with V8 or V10 engines.
01. Most Common Causes
- Faulty glow plug in cylinder 9
- Short to voltage in the glow plug circuit
- Open circuit in the glow plug wiring or connector
- Failed glow plug control module
- Corroded or damaged wiring harness
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Hard starting, especially in cold weather
- Rough idle or misfire on cylinder 9
- Excessive smoke from exhaust during startup
- Reduced engine performance
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all stored codes and freeze frame data.
Step 2: Visually inspect the glow plug wiring and connector for cylinder 9 for damage, corrosion, or shorts.
Step 3: Test the glow plug resistance with a multimeter; compare to manufacturer specs (typically 0.5-2 ohms).
Step 4: Check for voltage at the glow plug connector with key on; should be battery voltage (12V) during glow cycle.
Step 5: If voltage is present and glow plug is good, test the glow plug control module output to cylinder 9.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code, as it can cause hard starting, increased emissions, and potential damage to the glow plug system or engine. Have it diagnosed and repaired promptly.
How much does it cost to fix?▼
The cost to fix P069B typically ranges from $50 to $150 for a single glow plug replacement, but can be higher if the control module or wiring harness needs repair. Diagnostic fees may add $50-$100.