What to check when code 84 and 99 comes up ?

[Danish Farmer]

Hi gyes

My Silverado throws the codes 84 and 99. Both ones is supposed to be about the accelerator. Truck runs fine, have not noticed any thing odd.
Is it an early warning that I have to replace some thing ?
It throws a bunch of codes regarding the EGR too 32,33 and 36

Regards, Max

 

[racer55]

DTC 32 - EGR Circuit Error
DTC 33 - EGR Control Pressure/Baro Sensor Circuit High
DTC 36 - Injection Pulse Width Error (Time Long)

DTC 84 - Accelerator Pedal Position Circuit Fault
DTC 99 - Accelerator Pedal Position Sensor 5-Volt Reference Problem

The EGR codes might be from acracked vacuum line or bad wiring or a bad ground.

Code 36 will sometimes go away if you add a double dose of lubricity additive to the fuel,can also be PMD related.

The APP codes should also be lighting the service throttle soon light.
Sometimes if you spray the APP resistor pack with electrical contact cleaner and get it cleaned out well and follow up with some WD40 it can clear the codes.

The first thing I would do though is clean or repair the cluster of grounds at the rear of the intake manifold on the passenger side.