Throttle relearn not performed after battery disconnection, module reprogramming or throttle body replacement; Previous relearn aborted because ignition was switched off early or conditions such as coolant temperature or battery voltage were not met; Carbon build-up in the throttle body preventing the plate from reaching a consistent closed position; Low or unstable battery or charging system voltage during the learn procedure; Faulty throttle body, TP sensor or throttle motor, or wiring and connector fault in the throttle circuit; Faulty engine control module or outdated calibration (depends on model and engine).

P1526

TP Sensor Learn Not Complete.

GM
Powertrain
Manufacturer code
Medium severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
5: AreaVehicle speed, idle control and auxiliary inputs
26: FaultThe specific fault in that area

What it means

On GM vehicles P1526 means the throttle position (TP) sensor learn procedure has not been completed. The control module needs to learn the closed-throttle position of the electronic throttle body, and it set the code because that learned value is missing, for example after a battery disconnect, module replacement or throttle body replacement, or because a previous relearn attempt failed.

Symptoms

Engine warning light on
Unstable or high idle speed
Poor or delayed throttle response
Engine in reduced power or limp mode on some models
Stalling or hesitation when pulling away
Other throttle-related codes stored alongside

Possible causes

Throttle relearn not performed after battery disconnection, module reprogramming or throttle body replacementlikely
Previous relearn aborted because ignition was switched off early or conditions such as coolant temperature or battery voltage were not metlikely
Carbon build-up in the throttle body preventing the plate from reaching a consistent closed positionpossible
Low or unstable battery or charging system voltage during the learn procedurepossible
Faulty throttle body, TP sensor or throttle motor, or wiring and connector fault in the throttle circuitpossible
Faulty engine control module or outdated calibration (depends on model and engine)rare

How to diagnose

Read all stored and pending codes and freeze frame data, and note any other throttle, pedal or voltage codes
Ask about recent work such as battery disconnection, throttle body cleaning or replacement, or module changes
Check battery condition and charging voltage, as the learn procedure needs stable voltage
Inspect the throttle body wiring and connector for damage, corrosion, water ingress or loose pins
Inspect the throttle body bore and plate for heavy carbon deposits and check the plate moves freely
Check live data for TP sensor readings and throttle commanded versus actual position
Clear the code and carry out the manufacturer's throttle relearn procedure for the specific model and engine, then recheck for the code
Check for a technical bulletin or calibration update for your model if the code returns after a successful relearn

How to fix

Carry out the throttle position relearn procedure as specified for the model, ensuring the required conditions are met
Charge or replace a weak battery and repair any charging system fault, then repeat the relearn
Clean the throttle body using a method suitable for electronic throttles, then relearn
Repair damaged wiring or connectors in the throttle circuit
Replace a faulty throttle body and complete the relearn afterwards
Update the control module calibration only where a bulletin shows an outdated calibration is the cause

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but idle and throttle response may be poor and it could enter limp mode. Get the relearn done soon, and avoid driving if it stalls or hesitates dangerously.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.