P0667

PCM/ECM/TCM Internal Temperature Sensor Range/Performance

P0667 is a generic OBD-II powertrain diagnostic trouble code: PCM/ECM/TCM Internal Temperature Sensor Range/Performance. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P0667
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P0667 means

P0667 is stored when the powertrain control module detects that its internal temperature sensor signal is outside the expected range or is not performing consistently with other temperature references. Many PCMs include an on-chip temperature sensor used for thermal protection, compensation of internal calculations, and monitoring of operating conditions.

The PCM compares its internal temperature reading against plausibility limits and may cross-reference with ambient air temperature or engine coolant temperature to validate the reading. A value that is implausibly high, low, or erratic for the current operating conditions triggers this fault.

While this code does not always directly impair engine operation, it can mask or contribute to other faults if the internal temperature sensor is used for compensation functions. Persistent overtemperature conditions suggested by a faulty sensor could also prevent the PCM from activating appropriate thermal protection strategies.

Common causes

Most-frequently reported root causes when P0667 is logged.

  • 1
    Failed internal PCM temperature sensor or degraded on-chip sensing element.
  • 2
    PCM hardware fault causing abnormal internal thermal readings.
  • 3
    Excessive underhood temperatures causing the PCM to reach legitimate thermal limits.
  • 4
    Poor PCM mounting or missing heat shield allowing abnormal heat soak.
  • 5
    Damaged PCM connector or wiring causing reference voltage faults that affect internal sensor circuits.
  • 6
    PCM software fault causing incorrect interpretation of the internal temperature signal.
  • 7
    Moisture or corrosion ingress into the PCM causing sensor circuit faults.

Symptoms drivers notice

MIL illuminated with P0667 stored.
No immediately obvious drivability symptoms in mild cases.
PCM may limit certain functions if it believes it is overheating.
Other internal processor or reference codes may be stored alongside P0667.
In severe cases, reduced engine performance if thermal protection strategies are activated.

How to diagnose P0667

A typical diagnostic flow when this code is present.

  1. 1
    Record all stored DTCs and check for additional internal module codes that may indicate a broader PCM fault.
  2. 2
    Check the PCM mounting location for signs of heat damage, proximity to exhaust, or missing heat shields.
  3. 3
    Inspect the PCM main connector for moisture, corrosion, or damaged pins.
  4. 4
    Verify PCM supply voltage and ground quality.
  5. 5
    Compare ambient and coolant temperatures to the reported internal PCM temperature using live data if supported.
  6. 6
    If the PCM environment is thermally normal and external circuits are good, update PCM software if a calibration update applies.
  7. 7
    If fault persists with no external cause, the PCM likely has an internal hardware fault and may require replacement.

Related powertrain codes

Frequently asked questions

Can high underhood temperatures cause P0667?

Yes. Legitimate overheating of the PCM, such as from a missing heat shield or close proximity to exhaust components, can trigger this code without a PCM hardware fault.

Is P0667 a critical fault?

It is generally a warning-level fault. However, if the PCM cannot monitor its own temperature it may fail to protect itself from thermal damage over time.

Will replacing the PCM fix P0667?

If the internal sensor has failed, yes. But first eliminate external causes such as heat exposure, wiring faults, and software issues.

Can moisture in the PCM cause this code?

Yes. Moisture or corrosion inside the PCM connector or housing can corrupt internal sensor signals and trigger P0667.

Disabling P0667 in software

RaceTune can permanently disable P0667 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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