P2877

Exhaust Gas Temperature Sensor D Circuit Range/Performance (Bank 1)

P2877 is a generic OBD-II powertrain diagnostic trouble code: Exhaust Gas Temperature Sensor D Circuit Range/Performance (Bank 1). 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
P2877
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P2877 means

P2877 is stored when the ECM detects that Exhaust Gas Temperature (EGT) Sensor D on Bank 1 is producing a signal that is within the valid electrical voltage range but does not correspond to a physically plausible exhaust temperature given current engine operating conditions. EGT Sensor D is the fourth sensor in the exhaust temperature monitoring chain, typically located downstream of the SCR catalyst or at the tailpipe outlet, depending on the aftertreatment system layout.

The ECM cross-validates EGT readings against the thermal model derived from engine load, fuel flow, ambient conditions, and upstream sensor values. A sensor that reads implausibly hot or cold relative to the upstream sensors without a combustion or system event to explain the discrepancy triggers this performance fault. Common causes include a degraded thermistor that has shifted its characteristic curve, water intrusion into the connector, or excessive exhaust backpressure skewing the temperature gradient.

P2877 can interfere with SCR catalyst temperature management, DPF regeneration strategies, and exhaust system protection maps. If the ECM cannot trust EGT Sensor D, it may disable temperature-dependent aftertreatment strategies or use a conservative substitute value, potentially causing more frequent DPF regenerations or reduced SCR dosing efficiency.

Common causes

Most-frequently reported root causes when P2877 is logged.

  • 1
    EGT Sensor D thermistor element aged or shifted in output characteristic.
  • 2
    Moisture or coolant contamination in the sensor connector degrading the signal.
  • 3
    Intermittent contact in the sensor connector causing erratic temperature readings.
  • 4
    Exhaust system leak near the sensor altering the local temperature field.
  • 5
    Incorrect sensor installed with wrong calibration characteristic.
  • 6
    Wiring harness damage causing partial resistance in the circuit.
  • 7
    ECM temperature model deviation due to upstream sensor faults producing implausible comparisons.

Symptoms drivers notice

MIL illuminated with EGT performance DTC.
Possible more frequent or missed DPF regeneration events.
SCR catalyst dosing strategy may be altered, affecting NOx conversion efficiency.
No noticeable driveability change in many cases.
Possible companion upstream EGT or SCR efficiency DTCs.

How to diagnose P2877

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all DTCs and freeze frame data; note which EGT sensors in the chain may have companion faults.
  2. 2
    Monitor all EGT sensor live data simultaneously to compare the gradient from upstream to downstream during a drive cycle.
  3. 3
    Inspect EGT Sensor D connector and wiring for moisture, corrosion, or heat damage.
  4. 4
    Measure sensor resistance at the connector at a known temperature and compare against specification.
  5. 5
    Check for exhaust leaks in the vicinity of EGT Sensor D that could distort local temperature readings.
  6. 6
    Verify reference voltage and ground circuit integrity at the sensor connector.
  7. 7
    Replace EGT Sensor D if resistance is out of specification and all circuit checks are normal.

Related powertrain codes

Frequently asked questions

Where is EGT Sensor D typically located?

Sensor D is the fourth in the exhaust train. It is commonly placed after the SCR catalyst, though exact positioning varies by manufacturer and model.

Can an exhaust leak mimic a bad EGT sensor?

Yes. A leak near the sensor can draw in cooler ambient air, causing the sensor to read lower than expected and triggering a range/performance fault.

Is P2877 dangerous to drive with?

Generally not immediately dangerous, but aftertreatment management may be degraded. Prolonged operation can lead to a DPF or SCR system fault and an eventual derate.

Does replacing one EGT sensor require recalibration?

No recalibration is typically required for EGT sensors as they use a standard thermistor characteristic; the ECM reads resistance directly.

Disabling P2877 in software

RaceTune can permanently disable P2877 — 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 P2877 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.

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