Intake Air Heater (Glow Plug) Circuit Malfunction
What does POWERSTROKE-P0540-73 mean?
The POWERSTROKE-P0540-73 (Power Stroke) diesel fault code means: Intake Air Heater (Glow Plug) Circuit Malfunction. This is a moderate severity code.
Common Symptoms
- Hard cold start
- White smoke on start
- CEL
Probable Causes (Ranked by Likelihood)
- Failed glow plug relay (GPR) Very Likely
- One or more open glow plugs Likely
- Damaged valve cover gasket harness (injector/glow plug harness in valve cover) Likely
Step-by-Step Diagnostic Procedure
Test each glow plug resistance -- should be 0.5-2 ohms. Opens indicate failed plugs.
Test GPR -- should click and provide 12V to the glow plug bus bar for 10-120 seconds at cold start.
Inspect under valve cover harness for melted or rubbed wiring (classic 7.3L issue).
Frequently Asked Questions
What is P0540 on a 7.3L Power Stroke?
P0540 on a 7.3L Power Stroke (1994-2003) indicates: Intake Air Heater (Glow Plug) Circuit Malfunction. This is a known diagnostic trouble code on this engine family and typically points to the causes listed above.
Can I drive with P0540 on my Power Stroke?
Yes, you can generally drive with this code, but diagnose it soon to prevent further damage.
How much does it cost to fix P0540?
Repair cost is typically $100-$600 depending on the underlying cause and whether you DIY or use a shop. Diagnostic time alone runs $100-$180 at most independent diesel shops.