Faulty internal temperature sensor inside the reductant control module; Damaged or corroded wiring harness between the sensor and the module connector; Loose, bent, or backed-out pins at the module connector; Water intrusion or contamination inside the module housing; Internal circuit board fault in the reductant control module; Extreme cold ambient temperatures causing the sensor to read below its normal range; Poor ground connection for the reductant control module

DTC codes / P06xx · Computer and output circuits / P06F2

P06F2Reductant Control Module Internal Temperature Sensor Circuit Low

P06F2 means the reductant control module has detected a low-voltage condition on the internal temperature sensor circuit, which monitors the module's own operating temperature. The module compares the sensor signal to expected limits and sets this code when the voltage stays below the calibrated threshold for a set time.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

Symptoms you may notice

Illumination of the malfunction indicator lamp (MIL) on the dashboard
Often no symptoms besides the warning light, especially in mild weather
Reductant system may enter a limited-operation or derate strategy in some vehicles
Possible reduction in diesel exhaust fluid (DEF) dosing, leading to increased emissions
In rare cases, the module may shut down completely, preventing DEF injection
No noticeable change in engine performance during normal driving

Common causes, most likely first

Faulty internal temperature sensor inside the reductant control module
Damaged or corroded wiring harness between the sensor and the module connector
Loose, bent, or backed-out pins at the module connector
Water intrusion or contamination inside the module housing
Internal circuit board fault in the reductant control module
Extreme cold ambient temperatures causing the sensor to read below its normal range
Poor ground connection for the reductant control module

How to diagnose and fix it

Use a scan tool to verify P06F2 is current and check for related reductant system codes
Inspect the reductant control module connector and wiring for corrosion, damage, or loose pins
Measure resistance and voltage on the internal temperature sensor circuit according to the service manual
Check the module ground circuit for excessive resistance and repair as needed
If the sensor circuit tests within specification, replace the reductant control module
Clear the code and perform a reductant system relearn or adaptation procedure if required
Road-test the vehicle to confirm the code does not return and the DEF system operates normally

Why the module temperature sensor fails

The internal temperature sensor is not a serviceable part on most reductant control modules, so a confirmed sensor fault usually means module replacement.
A low-voltage code can be set by a poor ground connection rather than a failed sensor, so always check grounds before condemning the module.
Extreme cold weather can cause the sensor to read below its normal range and set this code temporarily; clear it and recheck after the vehicle warms up.
Water intrusion into the module housing is a common cause that technicians miss because the connector looks dry from the outside.
This code does not always mean the module is defective; a chafed wire in the harness can produce the same low-voltage signal.

Can I keep driving with P06F2?

You can usually drive the vehicle with this code, but the reductant system may enter a derate strategy that limits speed or power if the fault persists. Avoid long trips and have the fault diagnosed soon to prevent more severe reductant system codes.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.