Codes U1110, U0121 and U1120, ESP, BAS, ABS, Brake and check engine lights turned on?

Tiny
JSTOWE
  • MEMBER
  • 2009 DODGE GRAND CARAVAN
  • 3.3L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 210,000 MILES
On the instrument panel, the ESP, BAS, ABS, Brake, and check engine light came on and the speedometer no longer works. The fuel economy drops rapidly, I assume because it is not receiving any speed input. The tachometer works fine.

I have the following codes:
U1110 - Lost vehicle speed
U0121 - Lost communication with anti-lock brake module
U1120 - Lost wheel distance

I am wondering if this might be a bad abs wheel speed sensor or some other sensor/component. If so how do I determine which wheel the bad sensor is on?

Thank you for any guidance you have on this!
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Saturday, September 30th, 2023 AT 11:12 AM

1 Reply

Tiny
AL514
  • MECHANIC
  • 3,960 POSTS
Hello, these codes that are setting are the PCM (engine computer) indicating that it has lost communications with the ABS module, these are CANBUS network codes. The other codes are related. There are multiple networks on this vehicle, do you have your own scan tool?
The first thing to do is check the ABS module fuses, there are 4 in the TIPM fuse block in the engine compartment.

Did this happen while driving? or suddenly.
Something else that needs to be checked is if there is communication with any other modules on that specific network. Such as the Wireless Ignition Node, the Occupant Restraint Control module. Those modules are all on the same CAN C Bus 500k network, if communication is possible with the other modules, then the power and ground feeds all need to be checked to the ABS module. It might be that it has failed. If there is no communication with the other modules, then that network might have gone down, but the PCM is not setting codes for any other modules on the network.

I've added some diagrams to show which modules are on the CAN C (2nd diagram), the 3rd diagram is the C335 connector which is for the ABS to connect to the main wiring harness, it should be checked for corrosion or wire damage. Diagrams 4 and 5 show the C335 location in the engine compartment.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/can-scan-controller-area-network-easy
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Sunday, October 1st, 2023 AT 1:28 PM

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