RING-RETAINING 9J2935 - Caterpillar

System Operation Description:This procedure covers the following codes:
Table 1
Diagnostic Trouble Codes for the Digital Throttle Position Circuit
J1939 Code Description Notes
91-3 Accelerator Pedal Position 1 : Voltage Above Normal The Electronic Control Module (ECM) detects the following conditions:
The ECM has been powered for 3 seconds.
Diagnostic code 168-4 is not active.
There are no active 678 codes.
The setting for the upper diagnostic limit has been exceeded for one second.
If equipped, the warning lamp will come on. The diagnostic code will be logged.
29-3 Accelerator Pedal Position 2 : Voltage Above Normal
91-4 Accelerator Pedal Position 1 : Voltage Below Normal The ECM detects the following conditions:
The ECM has been powered for 3 seconds.
Diagnostic code 168-4 is not active.
There are no active 678 codes.
The setting for the lower diagnostic limit has been exceeded for one second.
If equipped, the warning lamp will come on. The diagnostic code will be logged.
29-4 Accelerator Pedal Position 2 : Voltage Below Normal
91-8 Accelerator Pedal Position 1 : Abnormal Frequency, Pulse Width or Period The ECM detects the following conditions:
The signal frequency from the digital throttle position sensor is equal to 0% or 100% for more than 2 seconds.
The ECM has been powered for at least 3 seconds.
Diagnostic codes 91-3, 91-4, 29-3 and 29-4 are not active.
There are no active 678 codes.
The ECM sets the Throttle Position to "0%".
If equipped, the warning lamp will come on. The diagnostic code will be logged if the engine is running. The diagnostic code will not be logged if the engine is cranking.
29-8 Accelerator Pedal Position 2 : Abnormal Frequency, Pulse Width or Period
678-3 ECU 8 Volts DC Supply : Voltage Above Normal The ECM detects the following conditions:
The 8 VDC supply is more than 8.8 VDC for more than one second.
The ECM has been powered for more than 3 seconds.
Diagnostic code 168-4 is not active.
The ECM will log the diagnostic code and the warning lamp will illuminate while this diagnostic code is active.
The engine may be limited to low idle.
678-4 ECU 8 Volts DC Supply : Voltage Below Normal The ECM detects the following conditions:
The 8 VDC supply is less than 7.2 VDC for more than one second.
The ECM has been powered for more than 3 seconds.
Diagnostic code 168-4 is not active.
The ECM will log the diagnostic code and the warning lamp will illuminate while this diagnostic code is active.
The engine may be limited to low idle.
An active diagnostic code may not cause any noticeable effect on engine response unless the voltage drops below 6.5 VDC. Also, use this procedure if the digital throttle position sensor is suspected of incorrect operation.If a fault occurs with the primary throttle, and a secondary throttle is installed, the engine will use the secondary throttle until the fault is repaired.If a fault occurs with the secondary throttle, the engine will use the primary throttle until the fault is repaired.If a functional throttle is not available, the following conditions will occur:
The engine will default to the limp home speed.
If the engine speed is higher than the limp home