P2135 — Throttle/Pedal Pos Sensor/Switch A / B Voltage Correlation

powertrain (engine/transmission)

Is it safe to drive?

Drive with caution Drive with caution. Many throttle faults put the car into limp mode with limited power — enough to reach a shop, not for highway trips. If the engine stalls or the pedal stops responding, do not drive.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P2135 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the throttle and intake air metering for damage, corrosion, chafing or poor contact.
Subsystem check Inspect and clean the throttle body; check that the plate moves freely.
Subsystem check Watch throttle position and MAF/MAP readings in live data while pressing the pedal — values should change smoothly.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2135 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P2135 (parts and labor, USD, independent shop rates): Replace the MAF or MAP sensor: $150–$400; Clean the throttle body: $80–$200; Replace the throttle body assembly: $250–$700. Overall, fixing P2135 usually costs between $80 and $700. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What does OBD2 code P2135 mean?

Throttle/Pedal Pos Sensor/Switch A / B Voltage Correlation (P2135): a powertrain (engine/transmission) fault affecting the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Most often caused by contaminated or failed MAF/MAP sensor, faulty throttle position sensor or pedal sensor, dirty throttle body or stuck throttle plate.

Will P2135 clear itself?

Sometimes P2135 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

Is it safe to drive with P2135?

Drive with caution. Many throttle faults put the car into limp mode with limited power — enough to reach a shop, not for highway trips. If the engine stalls or the pedal stops responding, do not drive.

What are the symptoms of P2135?

Drivers most often notice: Check Engine Light on, stalling when coming to a stop, unstable or high idle, limp-home mode with reduced power.

What is the most common cause of P2135?

The most common causes are: contaminated or failed MAF/MAP sensor, faulty throttle position sensor or pedal sensor, dirty throttle body or stuck throttle plate.

What does P2135 mean?

When P2135 appears on a scan, it means the control module has flagged a problem in the throttle and intake air metering: throttle/pedal pos sensor/switch a / b voltage correlation. The fault sits in the powertrain (engine/transmission) group of the OBD2 standard.

To set P2135, the control module compares live readings of the throttle and intake air metering against calibrated limits, usually over several drive cycles. Alongside the code it stores a freeze frame — a snapshot of rpm, load, coolant temperature and vehicle speed at the moment of failure. Reading that snapshot first saves diagnostic time.

Common symptoms of P2135

Check Engine Light on
stalling when coming to a stop
unstable or high idle
limp-home mode with reduced power
poor throttle response

What causes P2135?

failed electronic throttle motor
dirty throttle body or stuck throttle plate
contaminated or failed MAF/MAP sensor
wiring or connector faults in the throttle circuit
faulty throttle position sensor or pedal sensor
intake air leaks after the MAF sensor

How to diagnose P2135

Connect an OBD2 scanner, confirm P2135 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Visually inspect the wiring harness and connectors related to the throttle and intake air metering for damage, corrosion, chafing or poor contact.
Inspect and clean the throttle body; check that the plate moves freely.
Watch throttle position and MAF/MAP readings in live data while pressing the pedal — values should change smoothly.
Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2135 does not return.

How to fix P2135

Start with the cheapest and most common causes before replacing expensive parts:

Replace the MAF or MAP sensor — $150–$400
Clean the throttle body — $80–$200
Replace the throttle body assembly — $250–$700

How much does it cost to fix P2135?

Repair cost depends on which component actually failed. Typical scenarios for P2135 (parts and labor, USD, independent shop rates):

Replace the MAF or MAP sensor: $150–$400
Clean the throttle body: $80–$200
Replace the throttle body assembly: $250–$700

Overall, fixing P2135 usually costs between $80 and $700. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.