P212C

Code

Generic P — Powertrain

Throttle Position Sensor/Switch G Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 21 EN: 39 RU: 29

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Broken, chafed, or shorted signal wire to ground
Corroded or loose connector at throttle body or sensor
Failed throttle position sensor / switch G inside throttle body or pedal assembly
Poor sensor ground or reference voltage (5V) loss
Water intrusion or contamination at connector
Faulty engine control module (less common)

Symptoms

Check Engine MIL illuminated (P212C stored)
Reduced engine power or vehicle enters limp/reduced-throttle mode
Poor or erratic throttle response, hesitation or surging
Engine may idle poorly or stall in severe cases
Possible lack of acceleration or unexpected throttle behavior

What to check

Read freeze frame and related DTCs (look for other throttle/pedal codes)
Visual inspection of throttle body, pedal harness, and connectors for damage/corrosion
Scan tool: monitor live TPS G voltage/signal while moving throttle/pedal
Check for proper 5V reference and good ground at TPS connector (key ON, engine OFF)
Back-probe signal, reference, and ground pins; wiggle wiring harness while monitoring signal
Measure continuity and resistance between sensor connector and ECM pins

Signal parameters

Typical TPS signal range: ~0.5 V (closed) to ~4.0–4.5 V (wide open) — exact values vary by vehicle
Low/short condition: signal voltage near 0.0–0.2 V or abruptly dropping to 0 V
Reference voltage: ~5.0 V (±0.2 V) from ECM to sensor
Ground: near 0 Ω continuity to chassis/ECM ground; measured voltage at ground pin should be ≈0 V
Use scan tool to confirm smooth, proportional change of TPS voltage with throttle movement

Diagnostic algorithm

Retrieve all stored/pending codes and freeze-frame data. Note operating conditions when code set.
Perform visual inspection: connectors, pins, wiring harness along route to ECM, and any signs of contamination or physical damage.
With key ON engine OFF, back-probe TPS connector: verify 5V reference, sensor ground (~0V), and signal voltage. If reference missing or ground bad, trace supply/ground circuits first.
Monitor live TPS G signal voltage while slowly opening and closing throttle (or pressing pedal). Look for expected smooth change and absence of drop to near 0V. Wiggle wiring and connectors to reproduce fault.
If signal is low or 0V, isolate by measuring continuity from sensor signal pin to ECM signal pin. Check for short to ground on the wiring (disconnect connector and measure signal side to ground).
Repair any wiring issues (repair chafed wires, replace connectors, clean corrosion). Re-test after repair.
If wiring and supply/ground are good but signal remains low, replace the throttle position sensor/throttle body or pedal sensor assembly per manufacturer procedure.
If replacement does not clear the issue, verify ECM power/ground and consider ECM input circuit failure (rare). Consult manufacturer service information before ECM replacement.
Clear codes, perform road test and re-scan to ensure code does not return and vehicle operates normally.

Likely causes

Short to ground in the TPS G signal circuit (most common)
Corroded/loose connector at the throttle body
Defective TPS G/switch inside the throttle body
Bad sensor ground or missing 5V reference from ECM
Wiring damage from routing near moving parts or heat

Fault status

⚠️ Status

P212C — Throttle Position Sensor/Switch G Circuit Low: detected voltage on TPS G signal is lower than expected (open/short to ground or failed sensor).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours