P1401 Glow Plug Monitor Circuit Bank 2
The P1401 code indicates a fault in the glow plug monitor circuit for bank 2 on Ford diesel vehicles. The PCM detects that the feedback circuit from the glow plug relay is not responding as expected during the diagnostic sequence. This Ford-specific code applies to diesel engines with banked glow plug heating systems. The system monitor checks the control circuit integrity and relay response; if the PCM does not receive the relay operation confirmation signal for bank 2, or detects an open or short circuit in the monitor loop, it sets this code.
01. Most Common Causes
- Faulty bank 2 glow plug relay
- Damaged or out-of-spec resistance glow plugs in bank 2
- Open or shorted wiring in the bank 2 monitor circuit
- Corroded or damaged pins in the glow plug relay connector
- Internal PCM failure in the relay control circuit
- Blown glow plug circuit fuse
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Hard starting in cold weather
- Excessive white smoke on startup
- Reduced engine performance
03. Step-by-Step Diagnosis
Scan for codes and verify P1401 is present; check for related codes.
Inspect glow plug relay and fuse for bank 2; test relay operation.
Measure resistance of each glow plug in bank 2; replace any out of spec.
Check wiring and connectors in the monitor circuit for damage or corrosion.
If all else passes, test PCM output and consider PCM replacement.
1. Frequently Asked Questions
Is it safe to drive?▼
Yes, but you may experience hard starting and increased emissions. It's best to repair soon to avoid further issues.
How much does it cost to fix?▼
Typically $200-$600 depending on the cause; glow plug replacement is $150-$400, relay $50-$150, PCM $500-$1000.