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Isuzu NPR

Roger's

New Recruit
Mechanic
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Good day guys, so I have a GMC W4500, 4HE1 engine, its pretty similiar to the Isuzu NPR, im getting a flash code 19 thats giving me some headache. Anyone with any advice or solutions to help with this problem, would really appreciate it.
 

guido4475

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Good day guys, so I have a GMC W4500, 4HE1 engine, its pretty similiar to the Isuzu NPR, im getting a flash code 19 thats giving me some headache. Anyone with any advice or solutions to help with this problem, would really appreciate it.

I dont think many expeditors are going to have, or be familiar with a Zoom-Zoom. ( at least that's what I called my NQR when I had it. Loved that little underpowered truck. Excellent for local deliveries. An excellent truck overall.
 

Hino123

Active Expediter
Researching
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Roger you forgot to mention what year your W4 was. I attached the troubleshooting guide for a FC 19 from 1999-2004 take a look and see if it looks applicable to your unit. I have seen issues with the exhaust brake relay in the dash. I would perform your voltage and ground measurements from there as it is easily ascessable. Also the wires on the top of the transmission are known to fail. Inspect the connectors closely.
 

Hino123

Active Expediter
Researching
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Diagnosis Based on Diagnostic Trouble Code (DTC)
DTC 19 ABS Operation Signal (Wire Breaking/Short Circuit)
Explanation of Circuit: When the signal from Electronic Brake Control Module (EBCM) is supplied to the Transmission Control Module (TCM) the TCM judges the operating condition of the ABS.
The ABS operation signal is output from the EBCM to the TCM, the TCM inhibits the coast lock-up control.
Explanation of Test: The following numbers correspond to the numbers enclosed with a circle in the diagnosis chart.
(1) When the ABS is INACTIVE, the voltage between the TCM terminal (B230-11) and ground (B231-2 or B231-8) is 10 to 16V.
(2) When the exhaust brake cut relay is removed, the TCM terminal (B230-11) and ground (B231-2 or B231-8) is 0V.
Diagnostic Aids: A temporary failure may be caused by faulty connection, worn-away wire insulator or internal wire breaking of insulator.
Check if any of the following conditions is provided in the EBCM and TCM harness connector: Terminal positional shift, improper junction, lock damage, improper terminal shape or damage, faulty wire connection of terminal, and harness damage.
TCM Voltage Check: Refer to pages 7A2.
figure 7a2-dtc19
flowchart 7a2-5
 
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