P06F3: Reductant Control Module Internal Temperature Sensor Circuit High

What it means

Same as P06F0 with the signal voltage above the plausible range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.

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 monitors its internal temperature through a built-in sensor. P06F3 sets when that sensor's signal rises above the plausible range, which can point to an open sensor or a circuit fault that pulls the signal high.

Common causes

Most likely first.

1. Sensor internal open
2. Connector pins corroded - high contact resistance
3. Supply wire pinched against B+ source

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. Save freeze-frame data and review live reductant-module temperature readings for an implausibly high value or a signal that stays fixed.
2. Inspect the module connector for corrosion, moisture, loose terminals, or pins pushed back in the connector body.
3. Follow the sensor wiring and look for damaged insulation or a wire pinched against a power source.
4. Using the wiring diagram, test the signal circuit for an open or short to supply and compare results with the manufacturer's specification.
5. Wiggle the harness while watching live data, then assess the internal sensor and module after external circuit faults are excluded.

Common fixes

• Repair a loose, corroded, or water-damaged connector and restore its seal.
• Repair the signal wire if it is open or shorted to supply, then secure it away from power wiring.
• Replace the reductant control module if its internal temperature sensor is confirmed open and not separately serviceable.
• Clear the code and verify that the live temperature signal is plausible.

Can I keep driving?

Driving may be possible if the vehicle behaves normally, but an AdBlue/DEF warning or countdown can restrict future starts. Limit unnecessary trips and have the fault checked promptly.