DTC P1629 Theft Deterrent Fuel Enable Signal Not Received. Pontiac Grand Prix 1997

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 1997 🢒 Grand Prix 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 DTC P1629 Theft Deterrent Fuel Enable Signal Not Received

Fuel Control (VIN 1)
OBD II Symbol Description Notice

Circuit Description

The PASS-Key® II module produces the Theft Deterrent Fuel Enable signal when the ignition is ON and the proper key resistor pellet is sensed by the PASS-Key® II module. The PCM monitors the Fuel Enable signal during crank. If the proper signal is present on the Theft Deterrent Fuel Enable circuit, the PCM enables fuel delivery to allow the engine to start. If the PCM detects that the fuel enable signal is not present or incorrect while an attempt is made to start the engine, DTC P1629 will set. The engine will not start as long as this condition is present. If the problem also affects inputs to the PASS-Key® II module, the starter motor may be disabled. If this condition is present, refer to Theft Deterrent Systems for further diagnosis.

Conditions for Running the DTC

DTC P1626 is not present.
An attempt is made to start the engine.

Conditions for Setting the DTC

The PCM detects an incorrect signal on the Theft Deterrent Fuel Enable Circuit.
The above conditions are present for longer than 2 seconds.

Action Taken When the DTC Sets

•	The PCM will not illuminate the Malfunction Indicator Lamp (MIL).

•	The PCM will store conditions which were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

•	A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

•	DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for the following conditions:

•	Poor connection. Inspect the PCM and PASS-Key® II module harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

•

Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PASS-Key® II module, turn the ignition ON and observe a digital multimeter connected to the theft deterrent fuel enable circuit at the PASS-Key® II module harness connector while moving connectors and wiring harnesses related to the vehicle theft deterrent system. A change in voltage will indicate the location of the malfunction.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

DTC P1629 - Theft Deterrent System Fuel Enable Circuit Incorrect Signal Detected During Crank

Step	Action	Value(s)	Yes	No
1	Was the Powertrain On-Board Diagnostic (OBD) System Check performed?	--	Go to Step 2	Go to the Powertrain On Board Diagnostic (OBD) System Check
2	Important:: Before continuing diagnosis, ensure that the vehicle battery is fully charged. Attempt to start the engine. Does the engine crank?	--	Go to Step 3	Go to Theft Deterrent System in Electrical Diagnosis.
3	Turn OFF the ignition switch. Disconnect the Body Control Module (BCM). Turn ON the ignition switch. Using a J 39200 Digital Multimeter, measure voltage between the vehicle theft deterrent fuel enable circuit and the ground circuit at the BCM harness connector. Does voltage measure near the specified value?	5 V	Go to Step 4	Go to Step 6
4	Turn OFF the ignition switch. Reconnect the BCM. Turn ON the ignition switch. Backprobe the BCM connector to measure frequency between the vehicle theft deterrent fuel enable circuit and ground. Is the frequency between the specified values?	40-60 Hz	Go to Step 5	Go to Step 8
5	Turn ON the ignition switch. Clear DTC P1629. Attempt to start the vehicle. Does the vehicle start and continue running?	--	Refer to Diagnostic Aids	Go to Step 7
6	Check the vehicle theft deterrent fuel enable circuit for an open, short to ground, or short to voltage. If a problem is found, repair as necessary. Refer to Repair Procedures in Electrical Diagnosis. Was a problem found?	--	Go to Step 10	Go to Step 7
7	Check the theft deterrent fuel enable circuit for a poor connection at the PCM. If a problem is found, replace loose terminal. Refer to Repair Procedures in Electrical Diagnosis. Was a problem found?	--	Go to Step 10	Go to Step 9
8	Check for poor connections at the BCM. If a problem is found, replace loose terminal(s). Refer to Repair Procedures in Electrical Diagnosis. Was a problem found?	--	Go to Step 10	Go to Theft Deterrent System in Electrical Diagnosis.
9	Replace the PCM. Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Is action complete?	--	Go to Step 10	--
10	Clear DTCs. Observe VTD Fuel Disable on the scan tool while cranking the engine. Does VTD Fuel Disable display Active?	--	Go to Step 2	System OK