Exhaust Aftertreatment Glow Plug Circuit Low
The P26A1 code indicates a low voltage condition in the exhaust aftertreatment glow plug circuit. This circuit is used to heat the diesel particulate filter (DPF) or selective catalytic reduction (SCR) system to aid in regeneration and reduce emissions. A low circuit condition typically means the voltage is below the expected threshold, often due to a faulty glow plug, damaged wiring, or a poor electrical connection. This can prevent proper exhaust aftertreatment operation, leading to increased emissions and potential DPF clogging.
1. Most Common Causes
- Faulty exhaust aftertreatment glow plug
- Open or shorted wiring in the glow plug circuit
- Poor electrical connection or corroded terminals
- Failed glow plug relay or control module
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel efficiency
- Increased exhaust emissions
- Possible DPF regeneration issues
3. Step-by-Step Diagnosis
Step 1: Scan the vehicle for additional codes and freeze frame data.
Step 2: Visually inspect the glow plug wiring and connectors for damage or corrosion.
Step 3: Test the glow plug resistance with a multimeter; compare to specifications.
Step 4: Check voltage at the glow plug connector with the ignition on; should be battery voltage.
Step 5: Inspect the glow plug relay and fuse for proper operation.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can lead to DPF clogging and reduced engine performance. Short trips may be okay, but prompt diagnosis is advised.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the cause. A glow plug replacement is usually under $100, while wiring repairs may be slightly more.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.