VSBA voltage circuit?????

[AOneill]

Thats what the code I'm getting says, but it says reference signal in my haynes manual..were talking about a code 1635 in a 99 venture..anyway when the code sets, the fuel guage goes all wacky, transmission bucks and the idle is way up, weird eh?? Anyway hopefully one of you venture experts can steer me in the right direction..I've had everything apart under to hood for cleaning and general inspection but hav'nt replaced any parts yet, scared to start..
thanks Andy

[GregA]

Originally Posted by AOneill

Thats what the code I'm getting says, but it says reference signal in my haynes manual..were talking about a code 1635 in a 99 venture..anyway when the code sets, the fuel guage goes all wacky, transmission bucks and the idle is way up, weird eh?? Anyway hopefully one of you venture experts can steer me in the right direction..I've had everything apart under to hood for cleaning and general inspection but hav'nt replaced any parts yet, scared to start..
thanks Andy

Hi Andy,

Sorry to hear about your problems.

My manual says that reference voltage is used for the following sensors: Throttle Position (TP), Manifold Absolute Pressure (MAP), and the EGR Valve Pintle Position sensor.

But based on your other symptoms (fuel gauge in particular), I would guess that you have a loose or dirty connection (or two) going to the Power-train Control Module (PCM) or possibly the battery to the PCM. I believe the PCM is mounted inside the Air Cleaner housing.

I would start by measuring the reference voltage at one of those sensors (easiest to reach) and go from there. During the measurement, I would wiggle some wires around to see what happens.

Let us know what you find.

Take Care,

[AOneill]

thanks Greg, btw, what manual do you have? Is it more detailed than haynes and stuff

[GregA]

Originally Posted by AOneill

thanks Greg, btw, what manual do you have? Is it more detailed than haynes and stuff

You're Welcome.

Its a computer based manual which is no longer available.

Sometimes you can find the same information at autozone.com.

Take Care,

[GMMerlin]

Originally Posted by AOneill

Thats what the code I'm getting says, but it says reference signal in my haynes manual..were talking about a code 1635 in a 99 venture..anyway when the code sets, the fuel guage goes all wacky, transmission bucks and the idle is way up, weird eh?? Anyway hopefully one of you venture experts can steer me in the right direction..I've had everything apart under to hood for cleaning and general inspection but hav'nt replaced any parts yet, scared to start..
thanks Andy

The PCM uses the 5 Volt Reference A circuit as a sensor feed to the following sensors: The TP sensor, MAP sensor, EGR Valve Pintle Position sensor.
The PCM monitors the voltage on the 5 Volt Reference A circuit. If the voltage is out of tolerance, the PCM will set DTC P1635
Be sure to inspect PCM and engine grounds for being secure and clean.
Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the MAP display on the scan tool with the ignition ON, engine OFF while moving connectors and wiring harnesses related to the following sensors:
The MAP sensor.
The EGR valve.
A change in the MAP display will indicate the location of the fault.

[AOneill]

Once again thankyou for the advice, and yes the problems are back...But wait... its summer time and hot here now..No troubles all winter, just August..Weird eh..Only acts up in the summer.
Does the map sensor work with intake air tempurature?

Originally Posted by GMMerlin

The PCM uses the 5 Volt Reference A circuit as a sensor feed to the following sensors: The TP sensor, MAP sensor, EGR Valve Pintle Position sensor.
The PCM monitors the voltage on the 5 Volt Reference A circuit. If the voltage is out of tolerance, the PCM will set DTC P1635
Be sure to inspect PCM and engine grounds for being secure and clean.
Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the MAP display on the scan tool with the ignition ON, engine OFF while moving connectors and wiring harnesses related to the following sensors:
The MAP sensor.
The EGR valve.
A change in the MAP display will indicate the location of the fault.

['97ventureowner]

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