SPACER 8D2638 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with the circuit that is for the throttle position sensor. Also use this procedure if one of the diagnostic codes in Table 2 is active or easily repeated.Note: Some of the following codes may not be applicable for certain applications.Note: Performing steps within this procedure requires the use of a multimeter capable of measuring a PWM duty cycle and frequency. Refer to Table 1 for the tools recommended for the procedure.
Table 1
Recommended Tools    
146-4080 Digital Multimeter Gp    
7X-1710 Multimeter Probe    
326-4904 Adapter Cable As    
Table 2
Diagnostic Trouble Codes    
J1939 Code     CDL Code     Code Description
(code descriptions may vary)     Comments    
29-2     774-2     Accelerator Pedal Position 2 : Erratic, Intermittent, or Incorrect     The Electronic Control Module (ECM) has detected an invalid combination of positions for the multi-position switches.
The code is logged. If equipped, the warning light will come on.
Engine RPM defaults to a predetermined safe speed. The throttle switch is ignored by the ECM until the fault is cleared and the keyswitch is cycled.    
29-3     774-3     Accelerator Pedal Position 2 : Voltage Above Normal     The ECM detects signal voltage that is not in