P2673

Glow Plug Circuit High Voltage - Bank 2

P2673 is a generic OBD-II powertrain diagnostic trouble code: Glow Plug Circuit High Voltage - 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
P2673
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P2673 means

P2673 is set on diesel engines when the glow plug control module or PCM detects an unexpectedly high voltage condition on the glow plug circuit for cylinder bank 2. Glow plugs are used to preheat the combustion chamber on cold starts and may also be used for post-glow heating to reduce emissions and noise.

A high voltage condition on this circuit can be caused by a wiring fault such as a short to the supply voltage rail, an internal fault within the glow plug control module, or a failed glow plug that presents an abnormally high resistance causing voltage to remain elevated. The control module monitors the circuit voltage during the heating cycle and flags this code when it exceeds calibrated thresholds.

Depending on ambient temperature, this fault may not affect cold-start performance noticeably in warm conditions but can result in difficult starting in cold weather. Prolonged operation with a faulty glow plug system can also increase white smoke on start-up and elevate HC emissions.

Common causes

Most-frequently reported root causes when P2673 is logged.

  • 1
    Short to voltage on the glow plug supply wiring for bank 2.
  • 2
    Faulty glow plug control module outputting excessive voltage.
  • 3
    Open circuit in the glow plug ground path causing floating high voltage.
  • 4
    Failed individual glow plug with very high internal resistance on bank 2.
  • 5
    Corroded or high-resistance connector in the bank 2 glow plug harness.
  • 6
    PCM or glow plug relay fault supplying unregulated voltage to the circuit.

Symptoms drivers notice

MIL illuminated, often with a glow plug warning light.
Hard cold starting, especially in low ambient temperatures.
Increased white smoke from the exhaust during cold start.
Rough idle immediately after a cold start.
Possible increase in exhaust emissions on start-up.

How to diagnose P2673

A typical diagnostic flow when this code is present.

  1. 1
    Read all DTCs with a scan tool; note if individual glow plug codes are present alongside P2673.
  2. 2
    Inspect the glow plug wiring harness and connectors on bank 2 for damage, melting, or corrosion.
  3. 3
    With ignition off, measure resistance of each bank 2 glow plug; compare to specification and look for open-circuit plugs.
  4. 4
    Check the glow plug relay and control module output voltage during a commanded glow cycle using a multimeter or oscilloscope.
  5. 5
    Inspect ground paths for the glow plug circuit to ensure low resistance continuity.
  6. 6
    If module output voltage is out of range with good plugs and wiring, suspect the glow plug control module.
  7. 7
    Replace faulty components, clear codes, and perform a cold-start retest to confirm repair.

Related powertrain codes

Frequently asked questions

Will P2673 stop my diesel from starting?

In warm weather the engine may start normally, but in cold conditions hard starting or no-start is possible. The fault should be repaired before cold weather operation.

Can a single bad glow plug set P2673?

Yes. A glow plug with very high resistance can cause the circuit voltage to behave abnormally, triggering the high voltage code for that bank.

Is the glow plug control module the same as the glow plug relay?

Not always. Modern diesels use an electronic control module that actively regulates glow plug power and monitors feedback, whereas older systems use a simple relay. Check your vehicle type.

How many glow plugs are on bank 2?

Bank 2 contains the cylinders on the opposite side from cylinder 1. The number of plugs depends on the engine configuration; a 4-cylinder inline engine has no bank split, so this code applies to V-type diesel engines.

Disabling P2673 in software

RaceTune can permanently disable P2673 — 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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