P2166

Code

Generic P — Powertrain

Throttle/Pedal Position Sensor D Maximum Stop Performance

Brand: Generic

Type: P — Powertrain

Views: UK: 33 EN: 51 RU: 40

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Faulty throttle/pedal position sensor D (internal failure or contamination)
Damaged, corroded or disconnected wiring or connector to sensor D
Short to battery voltage or short to ground on the sensor signal circuit
Intermittent open circuit in signal, reference or ground wires
Incorrect reference voltage (5 V) or poor sensor ground
Throttle body mechanical interference or binding at closed (stop) position

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Reduced engine power / limp-home mode in some vehicles
Poor or inconsistent throttle response, hesitation or surging
Engine may stall at idle or have unstable idle
Throttle position readings inconsistent with pedal input on scan tool

What to check

Connect a capable scan tool; read DTCs and freeze frame data
Observe live data for all throttle/pedal position sensors (A/B/C/D) and compare values
Visually inspect sensor D connector for corrosion, bent pins, water ingress or damage
Backprobe sensor connector: check reference voltage (~5 V), sensor ground, and signal voltage
Wiggle wiring harness while monitoring signal for intermittent changes
Inspect throttle body for binding or mechanical interference at closed stop

Signal parameters

Reference voltage: typically ~5.0 V (varies by manufacturer)
Sensor signal: typical throttle/pedal sensor range ~0.5–4.5 V from closed to wide open (vehicle-specific)
At closed/stop position the signal is usually near the low end (~0.2–1.0 V) and should be steady
At maximum stop or open positions the signal approaches the high end (~3.5–4.5 V) depending on design
No rapid jumps, dropouts, or pegged values; sensors that disagree significantly from other channels indicate a fault

Diagnostic algorithm

Retrieve all stored codes and freeze frame data with a scan tool. Note vehicle conditions when the code set.
Compare live values of all throttle/pedal sensors (A–D). Look for a sensor pegged at/near max stop or inconsistent with others.
Visually inspect sensor D harness and connector for damage, corrosion, or loose terminals; repair as necessary.
Backprobe the sensor connector: verify reference voltage (~5 V), good ground, and measure signal voltage at closed and slowly moved throttle/pedal. Check for stable, linear change.
Wiggle the harness and connector while monitoring signal for intermittent faults; check for shorts to battery or ground if signal is erratic or pegged.
Inspect throttle body mechanical stop and linkage for binding or obstruction preventing proper closed position.
If wiring and connectors are good but signal abnormal, replace sensor D and retest.
After repairs, clear codes, perform required throttle/pedal relearn/calibration procedure if applicable, then road-test to confirm code does not return.
If fault persists after sensor and wiring repairs, check ECM input circuits and software updates or consult service information for manufacturer-specific tests.

Likely causes

Wiring/connector corrosion or loose pin at sensor D
Sensor D internal failure (stuck at high/erratic output near max stop)
Short to Vbatt or ground on the sensor signal wire
Throttle body mechanical stop interference or misalignment

Fault status

⚠️ Status

Stored DTC when Throttle/Pedal Position Sensor D reported maximum-stop or out-of-range performance; ECM detected sensor output inconsistent with expected values or with other position sensors.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours