P212B

Code

Generic P — Powertrain

Throttle Position Sensor/Switch G Circuit Range/Performance

Brand: Generic

Type: P — Powertrain

Views: UK: 27 EN: 111 RU: 34

AI status

Completed

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Page language: EN

Causes

Damaged or corroded TPS G connector or pins
Open, short to ground, or short to voltage in the TPS G signal wiring
Failed or intermittent throttle position sensor (TPS) G
Poor reference voltage (5V) or ground to the TPS
Contaminated or mechanically binding throttle body or sensor
Faulty ECM or internal ECU input circuit

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Reduced engine power or limp-home mode
Poor idle, stalling, or rough idle
Hesitation, surging or poor throttle response
Unstable or jumpy throttle position readings on a scan tool

What to check

Retrieve freeze frame and full scan-tool data for throttle position sensors (including TPS G if available)
Check for other related DTCs (other TPS codes, throttle actuator codes, power/ground faults)
Visually inspect TPS connector and wiring for damage, corrosion, or loose pins
Backprobe and record TPS G signal voltage and compare to expected range at key-on and during throttle movement
Verify reference voltage (~5.0 V) and ground at the TPS connector
Wiggle test wiring harness while monitoring live data for intermittent changes

Signal parameters

Reference voltage (Vref): approx. 4.75–5.25 V at TPS connector with key ON
Signal voltage (sensor output): typically ~0.3–1.0 V at closed throttle and ~4.0–4.5 V at wide open (vehicle-specific)
Signal should change smoothly and monotonically with throttle movement (no sudden jumps or drops)
Ground: near 0 V with low resistance to chassis
Typical TPS input impedance: often in the low kiloohm range (varies by sensor)

Diagnostic algorithm

Connect a scan tool, record freeze frame and live data for TPS G and related channels. Note at what conditions the code set.
Inspect the TPS connector and wiring harness for corrosion, damage, pin push-out, or water intrusion. Repair or replace damaged parts.
With key ON (engine OFF), backprobe TPS connector: verify Vref (~5 V) and ground are present. If missing, trace and repair Vref/ground circuits.
Backprobe the TPS signal wire and slowly operate the throttle manually (or have technician depress pedal) while monitoring signal voltage: confirm smooth monotonic change without jumps, dropouts, or exceeding expected limits.
Perform a wiggle test on wiring between TPS and ECM while watching live data for intermittent faults. Repair harness faults as found.
If wiring and connectors are good, remove the TPS (or throttle body assembly as required) and inspect the sensor and mounting for contamination or damage. Clean throttle body if needed.
If suspect, measure TPS resistance or output per manufacturer specification. Replace sensor if out of spec.
After repairs, clear DTCs, perform any required throttle position relearn/calibration procedure, then road-test and re-scan to confirm the fault does not return.
If problem persists with good sensor and wiring, consider ECM input circuit diagnosis or replacement per manufacturer diagnostic flow.

Likely causes

Loose or corroded connector at the TPS
Wire chafing causing intermittent short or open
TPS internal failure producing out-of-range voltage
5V reference or ground circuit fault
Throttle body carbon/deposits causing erratic sensor readings

Fault status

⚠️ Status

TPS/Switch G circuit out of expected range or performance. ECM detected signal outside expected voltage range or inconsistent behavior and stored P212B. MIL may be set and engine may enter reduced-power mode.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours