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Retarder not working

Allison fault code 64-12 retarder modulation request device fault.
1. Check

A. Retarder counts using DDR, to identify problem wires.

B. Wiring harness has no opens, short wires, or shorts to ground.

Retarder modulation sensor failed low

Pulled connections on rocker switch, joystick, ECU and connection and on retarder. Stop light connections good also. Wondering if anyone has any advice or has been down this road. Grounds? not to sure where there are.
Doug W.
96 36' U270 CSGI #4946
04 Toyota Tacoma 4x4
PNW

Re: Retarder not working

Reply #1 –
Retarder working properly now after being persistent  by checking and cleaning all connections, until I was able to clear code 64 - 12. This was the culprit under dash behind kick panel.
Doug W.
96 36' U270 CSGI #4946
04 Toyota Tacoma 4x4
PNW

Re: Retarder not working

Reply #2 –
What is that? What was the problem? As a fellow owner of a 96 I am curious and needing to commit to memory.
Alan & Gerri Ortiz
1996 U295 36 ft.
"Rocinante"
Hartwell, Georgia
1999 Subaru Forester
Build No. 4957 Motorcader 17399

Re: Retarder not working

Reply #3 –
Quote from: Alan & Gerri Ortiz –
What is that? What was the problem? As a fellow owner of a 96 I am curious and needing to commit to memory.

Bosch 12 volt relay for joystick function.  Unplugged sprayed with contact cleaner and code cleared.
Doug W.
96 36' U270 CSGI #4946
04 Toyota Tacoma 4x4
PNW

Re: Retarder not working

Reply #4 –
How did you know it WAS the relay?? Had you seen one before?
Glenn and Amy Beinfest
2001 36' U320
#5812
2014 Honda CRV

No Whining on the YACHT

Re: Retarder not working

Reply #5 –
Quote from: GleamB –
How did you know it WAS the relay?? Had you seen one before?

Didn't know it was the relay until the code cleared. Followed wires from
Touchpad, Joystick, Rocker switch to all connections, eliminating one at a time until code cleared.
Doug W.
96 36' U270 CSGI #4946
04 Toyota Tacoma 4x4
PNW