CM850 Electronic Control System – FAULT CODE 426

SAE J1939 Data Link – Cannot Transmit


Fault Code: 426
PID: S231
SPN: 639
FMI: 2
LAMP: None

SAE J1939 data link – cannot transmit. Communication between the ECM and another device on the SAE J1939 data link has been lost.

None on performance. J1939 devices possibly do not operate.

SAE J1939 Data Link Circuit

Circuit Description

Devices such as automatic braking system controllers, autoshift transmissions, vehicle electronic control module (ECM), automatic slip reduction systems, electronic displays, electronic information systems, electronic service tools, and vehicle electronic control unit(s) can communicate with the ECM over the J1939 data link. Messages sent from the devices are received by the ECM and used for controlling the engine. The ECM also transmits information to these devices over the J1939 data link.

Component Location

The ECM is located on the intake side of the engine, near the front. The J1939 data link wiring and the SAE J1939 devices vary by OEM options.

Shop Talk

This fault occurs whenever the ECM starts communicating with any other device using the SAE J1939 data link and then can no longer transmit on the data link. Possible causes could be the following: Unplugging an electronic service tool before keying off the ECM, the SAE J1939 data link having an intermittent electrical problem, and the ECM (or another SAE J1939 device) tying up communications because of an electrical problem or by sending too many messages without stopping.

Refer to Troubleshooting Fault Code t05-426

Last Modified:  08-Jul-2010