Possible Causes

PATS transceiver
PCM
electronic encoded ignition key

PINPOINT TEST 3: PATS RECEIVED INCORRECT KEY-CODE FROM IGNITION KEY TRANSPONDER

PINPOINT TEST 3		PATS RECEIVED INCORRECT KEY-CODE FROM IGNITION KEY TRANSPONDER
STEP	INSPECTION		ACTION
1	RETRIEVE THE DIAGNOSTIC TROUBLE CODES (DTCS) Key OFF. Key ON, Engine OFF (KOEO). Is DTC B1601 retrieved?	Yes	Go to next step.
1		No	The system is OK. CHECK all the customer's encoded ignition keys by attempting to start the vehicle with each key to verify all other encoded ignition keys are programmed.
2	CHECK FOR PROGRAMMED ENCODED IGNITION KEYS - MONITOR THE PCM PID NUMKEYS Does the PCM PID NUMKEYS display 8?	Yes	ERASE and REPROGRAM the key codes. See KEY PROGRAMMING USING DIAGNOSTIC EQUIPMENT . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
2		No	Go to next step.
3	CHECK THE NUMBER OF PROGRAMMED ENCODED IGNITION KEYS AVAILABLE Verify there are at least two currently programmed encoded ignition keys available with the vehicle. Are at least two currently programmed encoded ignition keys available with the vehicle?	Yes	Go to next step.
3		No	CUT a new encoded ignition key so that at least two encoded ignition keys are available. PROGRAM the encoded ignition keys. See KEY PROGRAMMING USING DIAGNOSTIC EQUIPMENT . Go to step 5.
4	VERIFY THE PCM PID SPARE_KY INDICATES YES Monitor the PCM PID SPARE_KY. Does the PCM PID SPARE KY indicate ENABLE?	Yes	Spare key programming is enabled. See KEY PROGRAMMING USING DIAGNOSTIC EQUIPMENT . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
4		No	ENABLE the PCM PID SPARE_KEY. See KEY PROGRAMMING SWITCH STATE CONTROL . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
5	CHECK THE ENCODED IGNITION KEYS FOR CORRECT OPERATION Key OFF. Turn the ignition switch to RUN for three seconds using the first encoded ignition key. Key ON, Engine OFF (KOEO). Turn the ignition switch to RUN for three seconds using the second ignition key. Start the vehicle using the second encoded ignition key. Does the vehicle start?	Yes	The system is OK. If there are additional keys that need to be programmed, See KEY PROGRAMMING USING DIAGNOSTIC EQUIPMENT .
5		No	Go to next step.
6	RETRIEVE THE DTCS - CHECK FOR DTC B1601 NOTE: When a new PCM is installed, the encoded ignition keys must be reprogrammed. Key OFF. Key ON, Engine OFF (KOEO). Is DTC B1601 retrieved?	Yes	Go to next step.
6		No	If other than PATS PCM DTCs are retrieved, See COMMUNICATIONS NETWORK . If no PATS DTCs are retrieved, the system is OK.
7	CHECK THE PCM FOR CORRECT OPERATION Disconnect all the PCM connectors. Check for: corrosion pushed-out pins Connect all the PCM connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present?	Yes	INSTALL a new PCM. See POWERTRAIN CONTROL MODULE (PCM) . REPROGRAM the encoded ignition keys. See KEY PROGRAMMING USING DIAGNOSTIC EQUIPMENT . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
7		No	The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.