Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2001 Pontiac Aztek Base, FWDFACTORY OEM SERVICE PROCEDURE
Water-In-Fuel Light Diagnosis
- Turn ignition on with engine off. If WATER IN FUEL light does not illuminate, go to next step. If WATER IN FUEL light illuminates briefly, go to step 5.
- Disconnect water-in-fuel sensor harness connector. Ensure ignition is on with engine off. Using an unpowered test light connected to ground, probe ignition feed circuit (Pink wire) at water-in-fuel sensor harness connector. See Fig 1. If test light illuminates, go to next step. If test light does not illuminate, go to step 6.
- Connect test light between ignition feed circuit (Pink wire) and ground circuit (Black wire) at water-in-fuel sensor harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 8.
- Using test light connected to ground, probe indicator light control circuit (Yellow/Black wire) at water-in-fuel sensor harness connector. See Fig 1. If test light illuminates, go to step 11. If test light does not illuminate, go to step 10.
- Operate vehicle under conditions when problem was noted. If system does not operate properly, go to step 2.
- Check for open in ignition feed circuit (Pink wire) between underhood fuse/relay center and water-in-fuel sensor. If problem exists, repair as necessary and go to step 12. If problem does not exist, go to next step.
- Check ignition feed circuit (Pink wire) for poor connection at water-in-fuel sensor. If problem exists, repair as necessary and go to step 12. If problem does not exist, go to step 11.
- Check for open in ground circuit (Black wire) between water-in-fuel sensor and ground connection. If problem exists, repair as necessary and go to step 12. If problem does not exist, go to next step.
- Check ground circuit (Black wire) for poor connection at water-in-fuel sensor. If problem exists, repair as necessary and go to step 12. If problem does not exist, go to step 11.
- Repair open in indicator light control circuit (Yellow/Black wire) between instrument cluster and water-in-fuel sensor. After repairs, go to step 12.
- Replace water-in-fuel sensor. After repairs, go to next step.
- Operate vehicle under conditions when problem was noted. If system does not operate properly, go to step 1.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.