P1635 Chevrolet

Question

I have a 1996 Chevrolet Camaro 3.8L automatic. I am getting a P1635 trouble code or 5 volt reference low reading. What does this mean, and where should I start looking. I notice my voltage gauge dropping low from time to time also. My A/C relay is getting a weak ground from the control green/white wire also. Is this a short, bad ground, voltage regulator, alternator, or PCM, or computer problem?

Answer 1

There are 3 circuit connected together: The Air Condition (A/C) Pressure sensor, the Manifold Absolute Pressure (MAP) sensor and the Engine Gas Recirculation (EGR) valve. If one of the sensor circuit is internally damage or the circuit is shorted you will get the P1635 code. Start by checking the connectors for the previously mention components.

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P1635 CHEVROLET - 5 Volt Reference Circuit

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