P212C: Throttle Position Sensor/Switch G Circuit Low

What does P212C mean?

P212C sets when position signal G reads below its lower electrical limit. The letter G only comes into play on engines with more than one electronic throttle. GM's 2023 and 2024 OBD tables (23OBDG07, 24OBDG07) give it to the second position sensor in the bank 2 throttle body of a twin-throttle engine: a raw voltage under 0.195 V lasting 0.14 s while the ECU is running stores the code within one trip. Usual culprits are a signal wire shorted to ground, a lost 5 V feed to that throttle body or a damaged sensor track. P212D is the matching high fault, P212A the general circuit code, P212B the plausibility check of G. Once a bank 2 signal is lost, the ECU typically restricts power.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Engine warning lamp on
• Reduced engine power message
• Uneven idle or hesitation on one bank

Common causes

• High Signal wire of sensor G shorted to ground
• Medium 5 V reference to the bank 2 throttle body open or pulled low
• Medium Worn or damaged track of position sensor G inside the throttle body
• Low Corroded or loose terminals at the bank 2 throttle connector

Likelihood is a general estimate across vehicles; your make and model may differ.