OBD-II Code P1125 — What It Means & How to Fix It

What Does This Error Mean?

P1125 means the Throttle Position Sensor (TPS) is Intermittent. The PCM has detected that the throttle position sensor signal is dropping out, spiking, or behaving erratically — but not failing consistently. Intermittent TPS faults cause unpredictable throttle response, hesitation, or sudden surges. Because the fault is not constant, it can be difficult to reproduce during diagnosis.

Affected Models

Common in GM vehicles with single and dual TPS monitoring
Common in Chevrolet, Pontiac, and Buick with 3.4L, 3.8L, and 4.3L V6 engines
Common in GM trucks with 4.3L, 5.0L, and 5.7L V8 engines
Also seen on Ford and Chrysler vehicles with TPS intermittent monitoring

Common Causes

TPS sensor with an internal wear spot or cracked resistive track causing intermittent voltage dropout
Loose or corroded TPS connector that makes intermittent contact during vehicle vibration
Chafed wiring that makes intermittent contact with ground or another wire
Worn throttle shaft with excess play causing the TPS to move unexpectedly
Carbon buildup on the throttle plate causing inconsistent throttle positioning

How to Fix It

Wiggle the TPS connector while monitoring the signal on a scan tool live data screen. A spike or dropout when the connector is moved confirms a connection fault.

This is the fastest way to reproduce an intermittent connector fault without road testing.
Slowly sweep the throttle manually (with the ignition on, engine off) while watching TPS voltage on a scan tool. Look for any flat spots or jumps in the voltage sweep.

A smooth, uninterrupted voltage sweep from idle to full throttle is what a healthy TPS produces.
Inspect the throttle shaft for excessive play. Grab the throttle plate and wiggle it — more than minimal movement suggests worn shaft bushings.

Excess shaft play causes the TPS to move erratically and produce intermittent signals independent of throttle pedal input.
Clean the throttle body if there is significant carbon buildup on the throttle plate or bore. Carbon can cause the plate to stick and snap, producing TPS spikes.

Use throttle body cleaner and a lint-free cloth. Do not spray cleaner directly into the bore on drive-by-wire vehicles — use cloth application only.
Replace the TPS if the sensor has a dead spot on the sweep test. Clear codes and monitor for recurrence over several drive cycles.

An intermittent fault may take multiple drives to confirm as fixed — check for stored or pending P1125 after a week of driving.

When to Call a Professional

TPS replacement costs $80 to $250. Throttle body cleaning costs $100 to $250. Wiring repair is $100 to $300. Full throttle body replacement on drive-by-wire vehicles is $200 to $600.

Frequently Asked Questions

Why is an intermittent TPS fault hard to diagnose?

Because the problem comes and goes, it may not be present when you take the car to a shop. The mechanic may not be able to reproduce the symptom during a test drive. Freeze frame data from the stored code gives clues about the conditions when the fault occurred.

Can a dirty throttle body cause P1125?

Yes — heavy carbon deposits on the throttle plate cause it to stick and suddenly snap open or closed. This produces rapid TPS voltage changes that trigger an intermittent code. A thorough throttle body cleaning sometimes resolves P1125 without sensor replacement.

Is P1125 safe to drive with?

Cautiously — intermittent throttle response can be unpredictable and potentially unsafe. Sudden hesitation or surging during highway merging or overtaking can be dangerous. Get it diagnosed and repaired promptly.