TPS calibration procedure

[unit6usa]

I just bought a new throttle position sensor for my '94 CK3500 4WD 6.5TD. Did I read somewhere that there is a simple way of calibrating the TPS? Else, is calibrating necessary? If not, I suppose I could just replace it and go. Also, I'm getting DTC #41 brake switch fault and DTC #87 High Ratio Error (just to name a few). Would either one of these "faults" keep my 4L80E tranny from shifting into OD? It shifts hard (if it shifts) into 3rd. Feels kinda like "limp mode" to me...but that's just me.

[More Power]

Your '94 uses an APP (Accelerator Pedal Position) module. The 1993 or earlier trucks with the mechanical fuel injection system used a TPS (Throttle Position Sensor). The APP is plug n play. However, I wouldn't replace the APP unless you were getting APP codes, and the related wiring checked out.

Jim

[unit6usa]

One of the codes received on my '94 CK3500 6.5TD DB4 pump 4WD 4L80E was #87 "high ratio error". What does that mean and to what does it refer to? Are there any other conditions that would generate this code?

[BobND]

There is a speed sensor at the input to the 4L80E tranny, and a speed sensor on the output shaft. If the sensors aren't seeing the correlation between the input and output speeds the 'puter is looking for, for the gear the 'puter has selected, a code is set.

[JohnC]

The brake switch can make the TCC lockup fail. Fix that first and see if the rest doesn't take care of it's self. The high ratio error could be related to the TCC not locking.

The "TPS" (APP) doesn't need any sort of calibration on a '94, but, like MP said, I don't see any reason for you to chantge it since there are no related codes.