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Home/DTC Codes/Pontiac/Sunfire/1995-2005 2.2L I4/P1631
P1631

Theft Deterrent Start Enable Signal Not Correct

1995-2005 Pontiac Sunfire 2.2L I4

High SeverityPowertrain

Description

The PCM received a start enable signal from the theft deterrent system, but the signal is not the expected value or pattern.

Symptoms

  • Vehicle will not start
  • Security light flashing
  • Engine cranks but does not fire

Common Causes

  • Faulty key transponder
  • Passlock sensor sending incorrect signal
  • BCM internal fault
  • Wiring issue corrupting signal

Diagnostic Steps

  1. Test theft deterrent signal at PCM
  2. Check key transponder
  3. Test Passlock sensor output
  4. Inspect wiring
  5. Attempt security relearn

Repair Notes

Perform security relearn. Replace Passlock sensor or BCM if signal remains incorrect.

Related Codes

P1626Theft Deterrent Fuel Enable Signal LostP1626Theft Deterrent Fuel Enable Signal LostP1626Theft Deterrent Fuel Enable Signal LostP1626Theft Deterrent Fuel Enable Signal LostP1626Theft Deterrent Fuel Enable Signal LostP1626Theft Deterrent Fuel Enable Signal LostP1626Theft Deterrent Fuel Enable Signal LostP1626Theft Deterrent Fuel Enable Signal LostP1629Theft Deterrent Cranking SignalP1629Theft Deterrent Cranking SignalP1629Theft Deterrent Cranking SignalP1629Theft Deterrent Cranking SignalP1629Theft Deterrent Cranking SignalP1629Theft Deterrent Cranking SignalP1629Theft Deterrent Cranking SignalP1629Theft Deterrent Cranking SignalP1632Theft Deterrent System - Fuel DisabledP1632Theft Deterrent System - Fuel DisabledP1632Theft Deterrent System - Fuel DisabledP1632Theft Deterrent System - Fuel DisabledP1632Theft Deterrent System - Fuel DisabledP1632Theft Deterrent System - Fuel DisabledP1632Theft Deterrent System - Fuel DisabledP1632Theft Deterrent System - Fuel Disabled

Other Powertrain Codes

P1631 on Other Vehicles

Pontiac Aztek

2001-2005 3.4L V6

Pontiac Bonneville

1990-1999 3.8L V6

Pontiac Bonneville

2000-2005 3.8L V6

Pontiac Bonneville GXP

2000-2005 4.6L V8

Pontiac Bonneville GXP

2000-2005 4.6L V8 Northstar

Pontiac Bonneville SSEi

1992-1999 3.8L Supercharged V6

Pontiac Bonneville SSEi

1992-1999 3.8L V6 Supercharged

Pontiac Firebird

1993-1997 3.4L V6

Common Questions

What does code P1631 mean on a 1995-2005 Pontiac Sunfire?

P1631 stands for "Theft Deterrent Start Enable Signal Not Correct". The PCM received a start enable signal from the theft deterrent system, but the signal is not the expected value or pattern.

What are the symptoms of P1631 on a Pontiac Sunfire?

Common symptoms of P1631 include: Vehicle will not start, Security light flashing, Engine cranks but does not fire.

What causes P1631 on a 1995-2005 Pontiac Sunfire?

Common causes of P1631 include: Faulty key transponder, Passlock sensor sending incorrect signal, BCM internal fault, Wiring issue corrupting signal.

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