P06F1: Reductant Control Module Internal Temperature Sensor Range or Performance

What it means

Same as P06F0 with the signal in plausible range yet not matching the engine bay environment.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The reductant control module manages parts of the diesel DEF/AdBlue aftertreatment system and monitors its internal temperature sensor for a plausible reading. P06F1 sets when the sensor signal is electrically plausible but its value or response does not match expected conditions, which can indicate sensor drift or a module or wiring problem.

Common causes

Most likely first.

1. Reductant control module temperature sensor drift or failure
2. Module power or ground problem
3. Damaged wiring or connector
4. Control module fault

Symptoms

• Check engine light or NOx warning on
• AdBlue/DEF level or quality warning
• Possible no-start countdown after ignore period
• Failed emissions inspection (NOx)

How to diagnose it

1. Record freeze-frame data and scan the engine and reductant modules for related temperature-sensor, DEF, power, ground, and communication faults.
2. Compare the reductant module's internal temperature reading with ambient and nearby temperature readings after the vehicle has had time to cool, using the manufacturer's diagnostic information.
3. Inspect the reductant control module connector and nearby harness for corrosion, loose pins, damaged insulation, or signs of heat or water ingress.
4. Check module power and ground, then test the temperature-sensor signal circuit according to the wiring diagram and manufacturer's specification.
5. If the reading remains implausible with sound wiring and supplies, follow the manufacturer's procedure to assess sensor drift or an internal reductant control module fault.
6. After repair, clear the faults and verify the temperature reading and any DEF or NOx warnings under suitable conditions.

Common fixes

• Repair damaged or corroded reductant-module wiring or connector terminals.
• Restore a faulty module power or ground connection.
• Replace the reductant control module if its internal temperature sensor is confirmed to drift or report implausible values.
• Repair or replace the control module only after its wiring and supplies pass the specified tests.
• Complete any required reset or relearn and verify that DEF and NOx warnings clear.

Can I keep driving?

The vehicle may remain driveable at first, but an unresolved reductant-system fault can bring a warning or a no-start countdown, depending on the vehicle. Check the dashboard for countdown messages and arrange repair promptly; do not assume the vehicle will continue starting indefinitely.