P067B

4 Glow Plug Control Circuit High

P067B is a generic OBD-II powertrain diagnostic trouble code: 4 Glow Plug Control Circuit High. It is logged by the engine control unit when the glow monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P067B
Group
Powertrain
System
Glow
Severity
Warning (MIL on)
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What P067B means

P067B is set when the PCM detects that its internal processing of the engine coolant temperature signal does not meet expected performance criteria. The ECM performs internal cross-checks on the ECT signal, comparing it against model-based temperature estimates, intake air temperature, and other thermal inputs to verify plausibility and consistency.

This code differs from standard ECT sensor codes (P0115-P0119) in that P067B specifically reflects an internal control module performance failure in processing or validating the ECT data, rather than a raw circuit voltage fault. The PCM may detect that its internal calculation of expected coolant temperature diverges from the measured value beyond allowable tolerances.

A faulty ECT reading used by the PCM can impact cold-start fueling, warm-up enrichment, fan control, and transmission temperature management. Depending on the default value used in limp mode, the engine may run rich or lean, affecting fuel economy and emissions.

Common causes

Most-frequently reported root causes when P067B is logged.

  • 1
    Faulty engine coolant temperature sensor providing a signal that passes raw circuit checks but fails internal plausibility tests.
  • 2
    Intermittent wiring fault in the ECT sensor circuit causing signal dropouts that fail performance monitoring.
  • 3
    Air pocket or low coolant level causing the ECT sensor to read inaccurately.
  • 4
    PCM internal processing fault affecting coolant temperature signal validation.
  • 5
    Corrupted PCM calibration causing incorrect ECT plausibility thresholds.
  • 6
    Thermostat fault causing coolant temperature to behave inconsistently with the PCM thermal model.
  • 7
    Contaminated or wrong-mix coolant affecting temperature sensor accuracy.

Symptoms drivers notice

MIL illuminated.
Possible rough cold-start or extended warm-up behavior.
Fuel economy changes due to incorrect warm-up enrichment.
Engine cooling fan may activate abnormally.
Other ECT or thermostat codes may accompany P067B.

How to diagnose P067B

A typical diagnostic flow when this code is present.

  1. 1
    Record all stored DTCs; check for companion ECT circuit codes (P0115-P0119) or thermostat codes (P0128) that indicate a sensor or cooling system fault.
  2. 2
    Check coolant level and condition; an air pocket near the sensor can cause erratic readings.
  3. 3
    Inspect the ECT sensor connector and wiring for damage, corrosion, or intermittent contact.
  4. 4
    Use live data to monitor ECT sensor reading from cold start through warm-up and compare to ambient air temperature and expected warm-up curve.
  5. 5
    Verify thermostat operation by observing the rate of coolant temperature rise during warm-up.
  6. 6
    If sensor and cooling system are normal, update PCM software if a calibration is available.
  7. 7
    If the fault persists with confirmed normal sensor and cooling system operation, evaluate PCM internal fault.

Vehicles where we've handled P067B

Platforms in our catalogue with confirmed P067B coverage.

BMW 320D
2016

Related powertrain codes

Frequently asked questions

How is P067B different from P0116 (ECT range/performance)?

P0116 reflects a fault detected by the standard ECT monitor comparing sensor voltage to expected ranges, while P067B indicates the PCM's internal cross-validation of the ECT signal has failed, suggesting the fault may originate within the module's processing logic.

Can low coolant level trigger P067B?

Yes. An air pocket around the coolant temperature sensor can cause an erratic or implausible reading that fails the PCM's internal performance check.

Will a bad thermostat cause P067B?

Possibly. If the thermostat is stuck open and the engine takes an unusually long time to reach operating temperature, the PCM's thermal model may flag the ECT signal as implausible.

Is it safe to drive with P067B?

Short-term driving is generally possible, but inaccurate coolant temperature data can affect fuel control and emissions. Have the fault diagnosed promptly to avoid potential catalyst damage from incorrect fueling.

Disabling P067B in software

RaceTune can permanently disable P067B — 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.

ECUs with a P067B disable in our catalogue

Confirmed coverage from our recipe database — we support many more families. Upload your file and our identifier will match it automatically.

  • Bosch EDC17C50 verified 1 software version

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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