P2675

Glow Plug Control Module Control Circuit High - Bank 2

P2675 is a generic OBD-II powertrain diagnostic trouble code: Glow Plug Control Module Control Circuit High - Bank 2. 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
P2675
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P2675 means

P2675 is the complement to P2674 and is set when the PCM detects a high voltage condition on the control signal circuit to the bank 2 glow plug control module. Instead of being stuck low, the signal is stuck at or near supply voltage when it should transition to a commanded state, or the PCM detects a voltage level that exceeds calibrated maximum thresholds on the line.

Common causes include a short to the vehicle supply voltage on the control wire, an open in the control signal circuit preventing the PCM from pulling the line low, or an internal fault in the glow plug module holding the input line high. The PCM continuously monitors the feedback on this circuit and flags P2675 when the voltage remains high outside of normal operating parameters.

As with the low-circuit code, the functional consequence is that the glow plug module may not be correctly commanded by the PCM. Glow plugs could remain energized longer than intended, leading to premature plug wear, or conversely may not cycle correctly, causing cold-start issues. The root cause should be identified using wiring inspection and module testing.

Common causes

Most-frequently reported root causes when P2675 is logged.

  • 1
    Short to battery voltage on the PCM-to-glow plug module control signal wire.
  • 2
    Open circuit in the control signal path preventing the PCM output from reaching the module.
  • 3
    Internal glow plug control module fault holding the control input high.
  • 4
    Damaged wiring contacting a voltage source in the engine bay.
  • 5
    Faulty PCM driver unable to pull the control signal low as commanded.
  • 6
    Corroded connector causing intermittent or fixed high-resistance open on the signal line.

Symptoms drivers notice

MIL and glow plug indicator light illuminated.
Cold-start difficulty or extended cranking in low temperatures.
Possible over-energization of glow plugs leading to premature failure.
White smoke from the exhaust on cold start.
Rough or unstable idle during engine warm-up.

How to diagnose P2675

A typical diagnostic flow when this code is present.

  1. 1
    Read all stored DTCs to determine if other glow plug or module codes are present.
  2. 2
    With the glow plug module connector unplugged, measure the voltage on the control signal wire at the harness side; it should not be at battery voltage if no short to power exists.
  3. 3
    If voltage is high with module disconnected, trace the wire toward the PCM looking for a short to a voltage source.
  4. 4
    Inspect all connectors in the circuit for corrosion, bent pins, or water ingress.
  5. 5
    With wiring confirmed good, reconnect the module and use a scan tool to command the glow plugs on; verify the control signal transitions correctly with a multimeter or oscilloscope.
  6. 6
    If the module does not respond correctly to commands, replace the glow plug control module.
  7. 7
    Clear codes and verify repair with a monitored cold start.

Related powertrain codes

Frequently asked questions

Can P2675 cause glow plugs to burn out prematurely?

Yes. If the control module is kept in an incorrect state, glow plugs may be over-energized, reducing their service life. Prompt diagnosis is recommended.

Should I replace all glow plugs when this code appears?

Not necessarily. P2675 is a circuit control fault, not a plug resistance fault. Diagnose the control circuit first; only replace plugs if individual plug codes are also present or plugs are found faulty during testing.

How is P2675 different from P2673?

P2673 refers to high voltage detected on the glow plug power supply circuit, while P2675 refers to high voltage on the control signal line the PCM uses to command the module.

Will this code prevent the engine from starting at all?

In moderate or warm ambient temperatures the engine can usually start. In very cold conditions the lack of proper glow plug preheating may result in hard or failed cold starts.

Disabling P2675 in software

RaceTune can permanently disable P2675 — 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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