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.
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HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN PASSENGER EXTENDED, 5.0 MREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 221 (ENGINE CONTROLS SELF-DIAGNOSTICS)DIAGNOSTIC TESTSDTC P1280: ACCELERATOR PEDAL POSITION CIRCUIT - SENSOR 2TEST DESCRIPTION
2001 Chevrolet Chevy Express G2500, Van Passenger Extended, 5.0 M
Test Description
2001 Chevrolet Chevy Express G2500, Van Passenger Extended, 5.0 MSECTION Test Description
WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers in the diagnostic procedure.
- 2
TP sensor 2 and the APP sensor 2 share a common 5-volt reference source. Diagnose DTC P1220 first if P1220 is also set. See DTC P1220: THROTTLE POSITION SENSOR 2 - VOLTAGE OUT OF RANGE . - 18
This test determines whether or not the TAC module can recognize a change in signal voltage. - 19
There are 3 separate 5-volt reference sources within the TAC module. TP sensor 1 and APP sensor 1 share 1 5-volt reference source, TP sensor 2 and APP sensor 2 share another common 5-volt reference source and APP sensor 3 uses the third by itself. This test determines whether the signal circuit is shorted to any 1 of the 5-volt reference circuits. If a short exists, the corresponding sensor voltage will be pulled low. - 20
The previous step found the signal circuit and a 5-volt reference circuit shorted together. This test isolates whether the short is in the harness or within the TAC module. - 26
When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
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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.