P2135 Two throttle or pedal position sensor signals (A and B) that should agree with each other don't

Throttle/pedal position sensor A/B correlation

P2135 in short

P2135 means two position sensors that should agree, usually the pair in the throttle body, are reporting different positions. Causes include a worn throttle position sensor, wiring or terminal faults, and on some GM vehicles a sensor cover. Expect reduced power or surging. If the engine loses power, drops to idle or stalls while moving, stop safely and tow.

Electronic throttle systems use two sensors for the same job so the computer can cross-check them. On most engines A and B are the throttle position sensor pair in the throttle body; on some, the label covers the pedal sensors.

If the two signals stop tracking each other, the computer can't tell which is right, so it sets P2135 and usually limits power. Surging, hesitation and a reduced-power message are typical.

Fixes on record vary: GM replaced throttle position sensor covers on many trucks and cars, repaired chafed harnesses and re-crimped terminals, Hyundai replaced the sensor with a software update, and Nissan reprogrammed the 2020-2021 Frontier where the code set with no drivability concern.

Most likely causes

  1. Worn or faulty throttle position sensor (or its cover on some GMs)

    Common general cause
    Why it ranks here
    The sensor pair is what's disagreeing; GM and Hyundai bulletins replace the sensor or its cover.
    What would change this
    Likelier if the two signals diverge at a particular throttle angle with good wiring.
    How to test the electronic throttle body

  2. Chafed harness, poor terminal crimps or bad connector

    Common general cause
    Why it ranks here
    KBB lists open or shorted sensor wiring, and GM traced P2135 to chafed harnesses and poor crimps.
    What would change this
    Likelier with intermittent faults that change with harness movement.

  3. Throttle body assembly fault

    Possible — needs testing
    Why it ranks here
    On many engines the sensors are built into the throttle body, so the assembly is replaced; Mazda's Tribute bulletin covers the throttle body.
    What would change this
    Likelier if other throttle codes are stored too.
    How to test the electronic throttle body

  4. Engine computer software

    Supported by vehicle data
    Why it ranks here
    Nissan's Frontier and Hyundai bulletins include computer updates for this code.
    What would change this
    Likelier if a bulletin covers the vehicle and the car drives normally.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read codes and watch both position signals in live data while slowly pressing the accelerator pedal with the key on and the engine off

    Low riskTool: OBD-II scan tool with live data

  2. With the ignition off, look at the accelerator pedal sensor connector and the throttle body connector for corrosion, backed-out pins or harness rubbing

    Low riskTool: Flashlight

  3. Test sensor reference, ground and signal circuits and compare sensor sweeps to the service manual

    Best left to a shopTool: Digital multimeter or scope

    Warning:Back-probing sensor and computer circuits can damage terminals or the computer; follow the maker's procedure.

Symptoms

  • Surging or hesitation
  • Reduced engine power message or limp mode Gets more serious: stop and have it checked.
  • Rough or unstable idle
  • Engine drops to idle or stalls while driving Gets more serious: stop and have it checked.

Compare with: Check engine light with loss of power

How to fix

  1. Ask a dealer to check your VIN for open recalls, bulletins or extended-coverage programs for the throttle body or pedal; several makers have published repairs for these codes.

  2. Write down when it happens (cold start, after rain or frost, at cruise, after a battery disconnect) and whether turning the engine off and on clears it. That detail helps the shop find an intermittent fault.

Parts and cost context

  • Electronic throttle body:Depending on the engine, the fix may be a sensor, a sensor cover, wiring or the whole throttle body; check bulletins before buying. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Chevrolet

  • 2005–2013 · Silverado

    Supported by vehicle data

    Reduced power with P2135; GM replaces the throttle position sensor cover. Whether the bulletin is still current is not verified.

  • 2006–2011 · Impala

    Supported by vehicle data

    Reduced power with P2135; sensor cover replacement. Whether the bulletin is still current is not verified.

  • 2006–2008 · HHR

    Supported by vehicle data

    Power reduced with P2135 from chafed wiring or poor ECM terminals. Whether the bulletin is still current is not verified.

  • 11-06-04-007CStatus unverified

    MIL, reduced power and P2135: replace throttle position sensor cover (trucks and SUVs)

    2005–2013silverado, tahoe, suburban, avalanche, colorado · issued · NHTSA 10137449

    Indicator lamp on, reduced power message and P2135; the throttle position sensor cover is replaced. Also GMC and Cadillac trucks and SUVs.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 12-06-04-003AStatus unverified

    P2135: replace throttle position sensor cover (cars and crossovers)

    2006–2011impala, malibu, equinox, uplander · issued · NHTSA 10246602

    MIL on, reduced engine power and P2135; the throttle position sensor cover is replaced. Also Buick Lucerne.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 08-06-04-022Status unverified

    P2135 with engine power reduced: inspect harness for chafing, re-crimp ECM terminals (HHR)

    2006–2008hhr · issued · NHTSA 10024788

    Intermittent check engine light and power reduced message with P2135; inspect the harness for chafing and re-crimp ECM terminals.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 09-06-04-016AStatus unverified

    P2101/P2135 with reduced power from poor terminal crimps (Aveo)

    2009aveo · issued · NHTSA 10034366

    Reduced power with P2101 and P2135 from poor terminal crimps.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Hyundai

  • 2006–2009 · Sonata

    Supported by vehicle data

    P2135 on V6 engines; throttle position sensor and ECM update. Whether the bulletin is still current is not verified.

  • TSB-10-FL-010Status unverified

    P2135/P0638 or cold rpm fluctuation: TPS replacement and ECM update

    2006–2010sonata, santa-fe, azera · issued · NHTSA 10034649

    P2135/P0638 or cold rpm fluctuation on 2.7L, 3.3L and 3.8L engines; the TPS is replaced and the ECM updated.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Mazda

  • 2009–2010 · Tribute

    Supported by vehicle data

    P2135 with rough idle or reduced power. Whether the bulletin is still current is not verified.

  • 01-007-13Status unverified

    P2135 with possible P2111/P0122, rough or low idle, reduced power (Tribute)

    2009–2010tribute · issued · NHTSA 10097316

    MIL or wrench light with P2135, possibly P2111 or P0122, with rough idle or reduced power.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Nissan

  • 2020–2021 · Frontier

    Supported by vehicle data

    P2135 with no drivability concern; ECM reprogram. Whether the bulletin is still current is not verified.

  • NTB21-080Status unverified

    P0223/P0507/P2135 with no drivability concern: ECM reprogram (Frontier)

    2020–2021frontier · issued · NHTSA 10202255

    MIL with P0223, P0507 and/or P2135 and no drivability concern; the ECM is reprogrammed.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Honda

  • 2003–2004 · Accord

    Supported by vehicle data

    Honda points to connector C281 for P2135. Whether the bulletin is still current is not verified.

  • 04012004Status unverified

    P2135: check connector C281 (Accord)

    2003–2004accord · issued · NHTSA 10009023

    P2135: check connector C281.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P2138Two accelerator pedal position sensor signals (D and E) that should agree with each other don't

    Same system Possible — needs testing

    P2138 is the matching correlation code for the pedal sensor pair (D/E).

  • P2101The engine computer sees a problem in the throttle actuator motor circuit or the motor's response, so actual throttle position doesn't match what was commanded

    Shares causes Supported by vehicle data

    GM's Aveo bulletin lists P2101 and P2135 from the same poor terminal crimps.

  • P2106The engine computer has limited engine power as a fail-safe because of a throttle control fault

    Primary / secondary Supported by vehicle data

    Likely primary: P2135. Ford bulletins show P2106 limp mode set as a result of P2135.

  • P2111The engine computer commanded the electronic throttle to close further but saw it stay more open than expected

    Shares causes Supported by vehicle data

    Mazda's Tribute bulletin says P2111 may be present with P2135.

All Electronic throttle and accelerator pedal codes

P2135 questions

Is P2135 a throttle or a pedal problem?

On most engines it's the throttle position sensor pair in the throttle body, but on some it covers pedal sensors. Live data showing which pair disagrees settles it.

Sources and review

  1. p2135 Code - Throttle/Pedal Position Sensor/Switch 'A'/'B' Voltage Correlation — Kelley Blue Book (KBB Service Advisor)
  2. 11-06-04-007C: MIL, reduced power and P2135: replace throttle position sensor cover (trucks and SUVs) — General Motors / NHTSA ,
  3. What You Should Know About Electronic Throttle Control — AA1Car (Larry Carley)
  4. NHTSA recall 26V081: Electronic throttle body gears may break (2024-2025 Nissan Rogue 1.5L VC-Turbo) — Nissan North America / NHTSA ,
  5. NHTSA ODI Preliminary Evaluation PE13-003: Electronic throttle body malfunction (2009-2013 Escape, Fusion, Mariner, Milan) — National Highway Traffic Safety Administration, Office of Defects Investigation ,
  6. SB-01-045-10: P2104/P2111 with possible fail-safe speed limit (CX-9) — Mazda North American Operations / NHTSA ,
  7. TSB-10-FL-010: P2135/P0638 or cold rpm fluctuation: TPS replacement and ECM update — Hyundai Motor America / NHTSA ,
  8. 08-06-04-022: P2135 with engine power reduced: inspect harness for chafing, re-crimp ECM terminals (HHR) — General Motors / NHTSA ,
  9. 09-06-04-016A: P2101/P2135 with reduced power from poor terminal crimps (Aveo) — General Motors / NHTSA ,
  10. 01-007-13: P2135 with possible P2111/P0122, rough or low idle, reduced power (Tribute) — Mazda North American Operations / NHTSA ,
  11. NTB21-080: P0223/P0507/P2135 with no drivability concern: ECM reprogram (Frontier) — Nissan North America / NHTSA ,
  12. p2138 Code - Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation — Kelley Blue Book (KBB Service Advisor)
  13. 04219: MIL and ETC lamps with both P2106 and P2135 — Ford Motor Company / NHTSA ,
  14. 12-06-04-003A: P2135: replace throttle position sensor cover (cars and crossovers) — General Motors / NHTSA ,
  15. 04012004: P2135: check connector C281 (Accord) — American Honda Motor Co. / NHTSA ,
Last reviewed
Written by
Saurabh K.
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