OBD-II code · Powertrain (generic)
P04D5 Exhaust Brake Input Circuit Low
Same as P04D3 with the signal voltage below the plausible range. The exhaust control valve modulates exhaust backpressure or routing (EGR feed, sound, regen support); a malfunction shifts torque mapping and may trigger limp mode.
Is it safe to drive with P04D5?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.6–1.8 h
- Emissions test
- Usually unaffected
- Parts involved
- Exhaust Brake Request Switch
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.