Trouble Shooting

WARNING: This page is about a different car, the 2002 Lexus GS 430 and 2002 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.

Trouble shooting of a engine immobilizer system complaint begins with verification of the customer problem. If problem occurs, go to step 3. If problem does not occur, go to next step.
If problem does not occur, review conditions under which problem occurred for customer and try to duplicate those conditions. For example, if the problem occurs on rainy days or during high humidity conditions, sprinkle water onto vehicle and see if malfunction occurs. DO NOT sprinkle water directly into engine compartment or onto electronic components. Visually inspect for signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary.

Preform pre-check. See PRE-CHECK under SELF-DIAGNOSTIC SYSTEM. Check a DTC and note if a code is output. Delete the DTC. Check if the DTC will be output once again, when the problem symptom is simulated based on the noted code.

When a normal code is output, go to PROBLEM SYMPTOM INDEX table.
When a malfunction code is output, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS table.

PROBLEM SYMPTOM INDEX

Symptom

Suspected Area ⁽¹⁾

Immobilizer Is Not Set (Engine Starts With Key Codes Other Than The Registered Key Code)

⁽²⁾

Engine Does Not Start

⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽²⁾

Security Indicator Is Always ON

⁽⁷⁾⁽⁴⁾⁽²⁾

Security Indicator Is Always ON (Although Code Has Been Registered In The Automatic Registration Mode, Indicator Is Not OFF)

⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽²⁾

Security Indicator Is OFF (When DTC Of Immobilizer Is Output)

⁽⁴⁾⁽⁵⁾⁽⁶⁾⁽²⁾

Security Indicator Is OFF (When DTC Of Immobilizer Is Not Output)

⁽⁴⁾⁽²⁾

Security Indicator Is Abnormally Blinking

⁽⁴⁾⁽²⁾

⁽¹⁾	Perform test procedures in order listed under suspected area.

⁽²⁾	Check the ECM. See PIN VOLTAGE TESTS .

⁽³⁾	Check that the key which did not start the engine has been registered and that it is possible to start with a already registered key.

⁽⁴⁾	Check the wire harness. See WIRING DIAGRAMS .

⁽⁵⁾	Check the transponder key coil. See TRANSPONDER KEY COIL under COMPONENT TESTS.

⁽⁶⁾	Check the amplifier by substituting with a known-good unit. Further diagnosis information is not available.

⁽⁷⁾	Check the security indicator by finishing the automatic registration mode because the mode might still remain.

Inspect circuit and parts. See DIAGNOSTIC TESTS .
After repairs have been completed, confirm that problem has been eliminated. Operate the system under same conditions recorded for original complaint. If problem is no longer present, repair has corrected problem. If problem is still present, further diagnosis and repair is required.