Throttle position relearn not performed after battery disconnection, module reprogramming or throttle body or module replacement; Learn routine interrupted by the ignition being switched off, or by electrical load or low battery voltage during the procedure; Dirty or carbon-fouled throttle body preventing the throttle plate from returning to its normal closed position; Faulty throttle position sensor or throttle body assembly giving out-of-range or erratic readings; Wiring or connector fault in the TP sensor circuit (poor terminal contact, chafed wire, corrosion) or weak reference or ground; Low battery voltage or charging system fault disrupting the learn; Fault inside the engine control module.

P1526

TP Sensor Learn Not Complete.

Cadillac
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 a Cadillac, P1526 means the engine control module has not completed the throttle position (TP) sensor learn routine, so it has no valid stored closed-throttle reference. The module sets it when the learn was interrupted, failed, or lost after a battery disconnect, module reset or throttle body work.

Symptoms

Malfunction indicator lamp on
Unstable or surging idle, or idle too high or too low
Stalling when coming to a stop or on throttle release
Hesitation or poor throttle response
Reduced power or limp-home throttle behaviour on some models

Possible causes

Throttle position relearn not performed after battery disconnection, module reprogramming or throttle body or module replacementlikely
Learn routine interrupted by the ignition being switched off, or by electrical load or low battery voltage during the procedurelikely
Dirty or carbon-fouled throttle body preventing the throttle plate from returning to its normal closed positionpossible
Faulty throttle position sensor or throttle body assembly giving out-of-range or erratic readingspossible
Wiring or connector fault in the TP sensor circuit (poor terminal contact, chafed wire, corrosion) or weak reference or groundpossible
Low battery voltage or charging system fault disrupting the learnpossible
Fault inside the engine control modulerare

How to diagnose

Read all stored and pending codes plus freeze frame data, and note whether other TP sensor, throttle actuator or battery voltage codes are present.
Ask about recent work: battery disconnection, throttle body cleaning or replacement, module replacement or reprogramming.
Check battery condition and charging voltage, as the learn needs stable voltage.
Inspect the throttle body bore and plate for carbon build-up and check the plate moves freely and returns fully closed.
Inspect the TP sensor wiring and connector for damage, corrosion, loose terminals and water ingress.
With a scan tool, watch the TP sensor reading at closed and fully open throttle and check it moves smoothly without dropouts.
Check the reference voltage and ground at the sensor connector against the manufacturer's data for your model.
Carry out the manufacturer's throttle relearn procedure for the specific model and engine, then clear the code and retest.

How to fix

Perform the manufacturer's TP sensor or throttle relearn procedure with stable battery voltage and all loads off, following the exact steps for your model.
Clean the throttle body using a method approved for the vehicle, then repeat the relearn.
Repair or replace damaged wiring, connectors or terminals in the TP sensor circuit.
Replace the throttle body or TP sensor if readings are erratic or out of range, then complete the relearn.
Replace a weak battery or repair the charging fault, then repeat the learn.

Can I keep driving?

Medium severity

The car can usually be driven short distances, but poor idle, stalling or hesitation can be unsafe in traffic. Get it checked soon, and avoid driving if it stalls or loses power.

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