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Chevy and GM TPS sensor: symptoms, tests, fitment

GM has built a huge range of engines with both cable and electronic throttles, so the first job is working out which one you have. After that the diagnosis is the same as any vehicle.

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Updated October 12, 2026Research based, specs vary by vehicle

TPS

Fig. A: the TPS lives on the throttle body

Short answer

On a GM engine with a cable throttle, the TPS is usually a separate three-wire sensor on the throttle body. On engines with an electronic throttle, the sensors are usually built into the throttle body. Diagnose with codes and a sweep test, then buy by VIN or the number on your old part. ACDelco is GM’s own parts brand; Standard Motor Products, Delphi, Dorman, Walker and Hitachi also sell GM-fit sensors.

First: which kind of throttle does your Chevy have?

TPS
Fig. 01Cable throttle: a separate sensor on the shaft.
MOTOR + TPS
Fig. 02Electronic throttle: the sensors are usually inside.

Open the hood and follow the intake tube from the air filter to where it meets the engine. That is the throttle body. If a cable from the gas pedal connects to a pulley on it, your Chevy has a cable throttle and the TPS is normally a separate sensor on the end of the throttle shaft. If there is no cable and the throttle body has a motor housing, it is an electronic (drive by wire) throttle, and the position sensors are usually built in. TPS vs throttle body explains the difference.

What is specific to GM

Older GM fuel-injected engines used a separate three-wire TPS, and listings such as Dorman’s 3-wire GM sensor still cover 1990s Buick, Chevrolet and Pontiac models. Some of those sensors are adjustable: BBK’s instructions for 1985 to 1997 Tuned Port and LT1 throttle bodies note that Tuned Port sensors are factory slotted and set to the factory voltage with a digital voltmeter. See how to adjust a TPS.

Many GM engines since then use electronic throttle bodies, where the fix for a sensor fault is usually the throttle body. RepairPal’s estimate for a 2011 Chevrolet Cruze throttle body replacement is $346 to $495, mostly parts (RepairPal).

Search terms such as LS, Duramax and specific model years all lead back to the same question: is your sensor separate, and what part number fits? Your VIN answers both.

Chevy TPS symptoms and codes

The symptoms are the same as on any vehicle: hesitation, surging, a rough or high idle, stalling, odd automatic shifts, and reduced power on electronic throttles. The generic codes are the same too:

Generic OBD-II throttle position codes. Titles from OBD-Codes.com; your maker may word them differently.

CodeGeneric titleIn plain EnglishGuide
P0120Throttle Position Sensor/Switch A Circuit MalfunctionThe signal is outside the range the computer expects.P0120 guide
P0121Throttle Position Sensor/Switch A Circuit Range/PerformanceThe signal does not match what the engine is doing (RPM, airflow).P0121 guide
P0122Throttle Position Sensor/Switch A Circuit Low InputThe signal voltage is too low, often an open or a short to ground.P0122 guide
P0123Throttle Position Sensor/Switch A Circuit High InputThe signal voltage is too high, often a lost ground or a short to voltage.P0123 guide
P0124Throttle Position Sensor/Switch A Circuit IntermittentThe signal drops in and out: wiring, a connector or a worn track.Codes hub
P2135Throttle/Pedal Position Sensor/Switch A/B Voltage CorrelationThe two sensors in an electronic throttle body disagree.P2135 guide

Chevy may add its own related codes and word the titles differently. Your service information has the exact set conditions.

Testing a Chevy TPS

The method is the standard one: check the 5 V reference and the ground, then back-probe the signal and sweep the throttle slowly, looking for jumps and dropouts. On electronic throttles, watch both throttle signals in live data while pressing the pedal rather than forcing the plate. Full steps: how to test a TPS sensor.

Buying a TPS for your Chevy

  1. 01

    ACDelco (GM OE)

    Best for: an exact match to the original

    • GM’s own parts brand
    • Usually the highest price
  2. 02

    Delphi

    Best for: an OE-supplier aftermarket option

    • Former GM parts arm
    • Sensor line includes TPS

    Source: Aftermarket News: Delphi expands OE replacement sensors

  3. 03

    Standard Motor Products or Dorman

    Best for: lower-cost replacements

    • Wide GM coverage
    • Match by part number

Brand notes: the TPS brand table on the home page. Cost: TPS replacement cost. Install: how to replace a TPS sensor.

Questions people ask

Can a Chevy TPS be adjusted?

Some older GM sensors can. BBK’s instructions for 1985 to 1997 GM Tuned Port and LT1 throttle bodies say Tuned Port sensors are factory slotted and should be set to the factory voltage with a digital voltmeter. Most others mount through round holes and are not adjustable.

Is ACDelco better than aftermarket?

ACDelco is GM’s parts brand and is the exact match by design. Aftermarket sensors usually cost less. Whichever you choose, match it to your VIN or the old part number.

Where is the TPS on a Chevy truck?

On the throttle body, at the end of the throttle shaft. Follow the air intake tube to the engine; the throttle body is where it bolts on. The exact side and access vary by engine.

Sources

  1. Dorman 84598 3-wire GM throttle position sensor listing
  2. BBK: 1985 to 1997 TPI/LT1 throttle body installation instructions (PDF)
  3. RepairPal: 2011 Chevrolet Cruze throttle body replacement cost
  4. Aftermarket News: Delphi expands OE replacement sensors

Last reviewed 2026-10-12. General guidance only: specs, procedures and fitment vary by vehicle, so confirm in your service manual and on the listing before you buy or wrench.