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P0850 Diagnostic Issue on Workhorse RV with 8.1L Big Block GM and Allison 2100 Transmission

Model: Workhorse RV Fault Code: P0850 Posted: 2017-03-13 18:11

March 13, 2017 This vehicle is a recreational vehicle (RV) built on a Workhorse chassis, equipped with a large-block GM 8.1-liter engine and an Allison 2100 transmission. While driving at speeds between 60 and 65 mph, the instrument cluster suddenly goes dark and the transmission fails to shift properly. The dashboard displays a J1939 error indicating no signal between the vehicle bus and the instrument cluster. Using an OBD-II and ABS diagnostic tool, a P0850 traction control fault code is detected. What does the P0850 code specifically mean in this context? How does it affect the overall performance of the RV? Any insights or solutions for this issue would be greatly appreciated. TomRvr

Related fault codes

P0850

Comments (3)

Anonymous 2017-03-13 18:47

March 13, 2017 P0850 - Traction Control system error code. Has anyone experienced this on a 2004 Workhorse RV with an 8.1L gasoline engine and Allison 2100 transmission? Thanks TomRvr

Anonymous 2017-03-14 08:58

This appears more like a transmission-related fault — likely indicating a shift range issue. A traction control problem would typically be coded with an alpha character such as B or C, not P0850. I'll need to verify the specific chassis model and year for detailed information and add it shortly.

Anonymous 2017-03-14 11:03

For Allison transmissions, a P0850 code often points to an issue with the Neutral/ Park (NP) switch located at the rear of the transmission. Check the NSBU (Neutral Safety Brake Unit) switch for proper operation and connectivity.