Truck Repair: fault codes, amp fuses, troubleshooting details


Question
I have a customers truck in my workshop with an isc 300 that has intermittent fault codes appearing.
i think i have fixed most of them but now it is coming up with 434 unswitched battery supply circuit and sometimes but not often 444 remote accelerator control circuit. i have checked plugs and terminals but am not exactly sure which ones to check as i have no manual. what does code 434 point to.

Answer
Adam,
i have sent you a reply a couple of days ago on this question perhaps you did not receive it. However, the full troubleshooting details is copyrighted and as such, i am not in a position to forward it to you. You can contact cummins rep. close to your area for further help in getting the detailed troubleshooting procedure.
in an nutshell, code 434 is unswitched battery Overview
CODE   REASON   EFFECT
Fault Code: 434PID: S251SPN: 627FMI: 2LAMP: YellowSRT:    Supply voltage to the electronic control module (ECM) fell below (+) 6.2 VDC
Code 434 - Unswitched Battery Supply Circuit

Circuit Description
The ECM receives constant voltage from the batteries through the unswitched battery wires that are connected directly to the positive (+) battery post. There are three in-line 7.5-amp fuses and two 10-amp fuses in the unswitched battery wires to protect the engine harness from overheating. The ECM receives switched battery input through the vehicle keyswitch wire when the vehicle keyswitch is turned on.
Component Location
The ECM is connected to the battery by the engine harness. This direct link provides a constant power supply for the ECM. The location of the battery will vary with the equipment manufacturer. Refer to the equipment manufacturer repair manual.
Shop Talk
If the ECM unswitched battery supply is taken from the starter, check for low voltage during cranking. Low voltage during cranking can cause the ECM power supply to drop below specifications and log Fault Code 434