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)
Need P067B disabled?
RaceTune permanently disables any OBD-II trouble code on supported ECUs — for motorsport, off-road, and export use.
→

What P067B means

P067B is a generic diesel powertrain code set when the engine control module detects a higher-than-expected voltage in the glow plug control circuit for cylinder 4. Glow plugs are used on diesel engines to preheat the combustion chamber because these engines ignite fuel by compression rather than by a spark. The glow plug control module energizes each plug on a controlled duty cycle and feeds circuit feedback to the ECM so it can confirm that each plug is being driven correctly.

When the ECM commands the cylinder 4 glow plug but reads a voltage above the calibrated range, or finds the circuit electrically high when it expects it to be low, it stores P067B and usually turns on the malfunction indicator lamp. A high circuit is most often caused by an open in the control wiring, a failed glow plug, a corroded connector, or a control module output that is not switching correctly.

Typical symptoms include difficult cold starting, rough idle during warm-up, white exhaust smoke, and occasionally a flashing glow plug lamp. Because a single glow plug or its wiring can trigger the code, the individual plug and circuit should be verified before replacing the control module or ECM. Addressing the fault promptly restores reliable cold starting and reduces cold-start emissions.

Common causes

Most-frequently reported root causes when P067B is logged.

  • 1
    Open or high-resistance control wiring to the cylinder 4 glow plug.
  • 2
    Failed or open-circuit cylinder 4 glow plug.
  • 3
    Corroded or loose connector at the glow plug or control module.
  • 4
    Faulty glow plug control module driver for cylinder 4.
  • 5
    Damaged or chafed harness between the module and cylinder 4 glow plug.
  • 6
    Poor power supply or ground at the glow plug control module.
  • 7
    ECM fault misinterpreting the circuit feedback (rare).

Symptoms drivers notice

Malfunction indicator lamp illuminated.
Hard cold starting.
Rough running or misfire-like behavior until warm.
White or grey smoke from the exhaust on cold start.
Glow plug indicator lamp may flash or remain on.
Reduced power or hesitation in cold weather.

How to diagnose P067B

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve and document all stored DTCs and freeze frame data with a scan tool before clearing.
  2. 2
    Check for additional glow plug codes on other cylinders, which suggests a control module or supply issue rather than a single plug.
  3. 3
    Inspect the cylinder 4 glow plug connector and wiring for corrosion, chafing, or loose terminals.
  4. 4
    Measure cylinder 4 glow plug resistance against specification to identify an open or shorted plug.
  5. 5
    Test continuity of the control wire from the glow plug control module to the cylinder 4 glow plug.
  6. 6
    Confirm supply voltage and ground at the control module during the preheat cycle.
  7. 7
    If the plug and wiring test good, evaluate the control module output for the cylinder 4 channel.

Vehicles where we've handled P067B

Platforms in our catalogue with confirmed P067B coverage.

BMW 320D
2016

Related powertrain codes

Frequently asked questions

Is it safe to drive with P067B?

It is best to repair it promptly; a faulty glow plug causes hard cold starts, rough warm-up running, and higher emissions, and it can worsen if ignored.

How do I test the cylinder 4 glow plug?

Measure its resistance with a meter and compare to specification, or apply battery voltage on the bench and confirm the tip glows; an open plug will not heat.

Could the control module cause P067B instead of the plug?

Yes, a failed driver in the glow plug control module can leave the circuit reading high, so the module output should be checked if the plug and wiring are good.

Why does only cylinder 4 set the code?

The ECM monitors each glow plug circuit separately, so P067B specifically identifies the cylinder 4 circuit as the one measuring high.

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.

ECU families we can disable P067B on

We hold the DaVinci A2L disable definitions for these families, so the exact P067B path and mask addresses are mapped. verified marks a confirmed disable definition. We support many more — upload your file and our identifier will match it automatically.

  • Bosch EDC17C50 verified
  • Bosch EDC17C56 verified
  • Bosch EDC17C60 verified
  • Bosch EDC17CP44 verified
  • Bosch MD1CP002 verified
  • Bosch MD1CP004 verified
  • Bosch MD1CS001 verified

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.

Got P067B in your scan?

Upload your ECU file — we'll identify the exact software version and confirm whether a disable is available for your car.

Upload your file