OBD-II code · Powertrain (generic)
P04D6 Exhaust Brake Input Circuit High
Same as P04D3 with the signal voltage above 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 P04D6?
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 supply
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
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
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.