Faulty or unprogrammed ignition key or transponder not matching the vehicle; Communication fault between the security module and the engine control unit, such as wiring or connector damage; Faulty immobiliser antenna or ring around the ignition barrel, or key reader fault; Low battery voltage or poor power and earth supply causing communication dropouts; Replacement engine or security module that has not been correctly matched to the vehicle; Internal fault in the engine control unit or the security module.

P1502

Theft Deterrent System No Password Received.

Chrysler
Powertrain
Manufacturer code
Medium severity

How this code is built

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

What it means

On Chrysler vehicles, P1502 means the engine control unit did not receive the expected security password from the theft deterrent (immobiliser) system. The engine computer expects a valid coded message from the security module, and when it is missing or wrong it limits or prevents engine running. The exact modules involved depend on the model and year.

Symptoms

Engine cranks but will not start
Engine starts then stalls after a second or two
Security or immobiliser warning light on or flashing
Intermittent no-start that comes and goes
Key not recognised or no response when turning the ignition on

Possible causes

Faulty or unprogrammed ignition key or transponder not matching the vehiclelikely
Communication fault between the security module and the engine control unit, such as wiring or connector damagelikely
Faulty immobiliser antenna or ring around the ignition barrel, or key reader faultpossible
Low battery voltage or poor power and earth supply causing communication dropoutspossible
Replacement engine or security module that has not been correctly matched to the vehiclepossible
Internal fault in the engine control unit or the security modulerare

How to diagnose

Read all stored and pending codes and freeze frame data, noting any security or communication codes in other modules
Try every available key, and check the key is not damaged or fitted with a second key or metal fob close to the ignition barrel
Check battery condition and charging voltage, and fix any low voltage before further diagnosis
Inspect the wiring, connectors and earths for the security module, antenna and engine control unit for damage, corrosion or water ingress
Check the security light behaviour with the ignition on and compare it to the manufacturer's expected operation for the model
Use a scan tool to view the immobiliser status and check whether the key is being read and the modules are communicating
Test the communication circuit between the modules against the wiring diagram for the specific model
Confirm any recently replaced modules were programmed and matched to the vehicle as the manufacturer specifies

How to fix

Reprogram or replace the key so it is correctly matched to the vehicle
Repair damaged wiring, connectors or earths in the security communication circuit
Replace a faulty immobiliser antenna or key reader
Restore a healthy battery and charging system supply
Carry out the manufacturer's module matching and security programming procedure after any module replacement
Replace the faulty security module or engine control unit, then program it to the vehicle

Can I keep driving?

Medium severity

If the car starts and runs normally, it can be driven but get it checked soon as it may fail to restart. If it is stalling or not starting, it should not be relied on until repaired.

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