OBD Guide

P04D6

Exhaust Brake Input Circuit High

P04D6 is an OBD-II diagnostic trouble code meaning: Exhaust Brake Input Circuit High. Common causes: short circuit to power in the switch signal circuit, stuck engine brake switch. Estimated repair cost: $22–100.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$22–100 (est.)

Symptoms

  • Check Engine Light Is On
  • The engine brake may engage involuntarily or may not work
  • Reduced braking performance on descents
  • Possible jerking when driving in engine braking mode

Causes

  • Short circuit to power in the switch signal circuit
  • Stuck engine brake switch
  • Damage to wire insulation
  • Moisture getting into the connector
  • ECU malfunction

How to Fix

  1. Read error codes and capture freeze frame data
  2. Find the engine brake switch according to the diagram
  3. Check the voltage in the signal circuit with the switch off
  4. Disconnect the switch connector and check for voltage on the wire (if present, short to power)
  5. Check the resistance of the switch and the serviceability of its contacts
  6. Repair short circuit or replace damaged wire
  7. Replace the switch if necessary
  8. Reset the error and check the system operation

Related codes

Error P04D6 by Vehicle Brand

FAQ

What does the P04D6 code mean?

P04D6 is an OBD-II diagnostic trouble code that indicates: Exhaust Brake Input Circuit High

What causes a P04D6 error code?

The most common causes of P04D6 include: Short circuit to power in the switch signal circuit; Stuck engine brake switch; Damage to wire insulation; Moisture getting into the connector.

How do I fix a P04D6 diagnostic trouble code?

To fix P04D6: Read error codes and capture freeze frame data. Find the engine brake switch according to the diagram. Check the voltage in the signal circuit with the switch off. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P04D6?

Yes, but get it checked soon

How much does it cost to fix P04D6?

The estimated repair cost for P04D6 is $22–100. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat