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2002 Chevrolet Silverado 5.3L 4x4 P1639 Code: Causes, Symptoms, and Fixes

Model: 2002 Chevrolet Silverado Fault Code: P1639 Posted: 2010-04-11 15:08

I own a 2002 Chevrolet Silverado with a 5.3-liter engine and 4-wheel drive. After scanning the vehicle, I received a P1639 diagnostic code. The truck exhibits hesitation during freeway driving, and when parked, the idle RPM consistently ranges between 1200 and 1350. I'm looking for guidance on which sensor or sensors to check first to resolve this issue. Any insights into potential causes related to the P1639 code would be greatly appreciated.

Related fault codes
P1639
Comments (1)
Anonymous 2010-04-17 09:47

A previous owner reported that water ingress had reached terminals 45, 46, 47, and 48 at the PCM connector (C1 blue), leading to corrosion. After cleaning these terminals, the truck's performance improved significantly and ran smoothly.