P1632: Theft Deterrent System, Fuel Disabled (GM)
Severity: medium
What it means: P1632 is a GM code meaning the anti-theft system told the engine computer to disable the fuel. It usually shows up when the system didn't recognize the key or lost its signal, so the engine starts and then dies.
Safe to drive? The car won't run reliably while this is happening, so the main risk is getting stranded.
Common symptoms
- Starts and dies right away
- Security light on or flashing
- Intermittent no-start
Likely causes, ranked
- Weak battery or poor connectionsDIY
- Worn ignition lock cylinder or switchShop
- Blown fuse or body control module problemShop
- Theft-system code needs relearningShop
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Vehicle-specific notes
- 1995–2005 Pontiac Sunfire: On Car Talk, a 2001 Sunfire owner found P1632 along with P1626 after intermittent start-and-die episodes; members said to fix the weak battery first. Read the full answer · Source
DIY or shop?
DIY for battery, cable and fuse checks. Theft-system repairs are usually shop jobs.
Before you replace parts
- Test the battery and clean the battery cables first.
- Read all codes with a scanner that can read GM body and theft-system codes.
- Check your VIN for ignition switch recalls at nhtsa.gov/recalls.
- Have the ignition lock cylinder and Passlock sensor wiring checked before replacing the computer.
Safety / mechanic note
Verify with a mechanic. An anti-theft shutdown can leave you stranded. A code points to a circuit or system, not always a specific part.
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