New ECM, but it's still not working

We recently assisted a customer with a Fiat Scudo 120 Multijet, fitted with an RHK engine.

This vehicle came into his workshop as a non-running vehicle. The DTCs on the ECM were endless. Codes were present for Reference voltage error, Analog to Digital converter, Internal memory error, EGR circuit fault, MAF sensor signal fault to name just a few.

After extensive circuit testing with our help, the mechanic decided to order a Picoscope to be able to test the CAN signals to a deeper level. When the scope arrived, and after a few lessons from the Helpline to get him used to the scope, CAN signals were analysed, proving an issue was present.

A new ECM was ordered from Fiat and fitted, but it would not communicate when initial module programming was started. More testing with the scope indicated CAN was good, but no communications with the scan tool were occuring. Due to a lack of dealer equipment, the vehicle was sent to Fiat for module programming. The dealer also failed to communicate with the new module. Due to the age of the car, they wanted to replace the body module and wiring loom to proceed.This was not acceptable to the customer, so the car was returned for more closer inspection.     

After close inspection of the new ECM and bench testing revealed communication issues, the ECM was opened for inspection, only to find water damage was present in the new unit. The ECM was date checked, revealing a manufacture date of 2007. The ‘new’ ECM had been sitting around in the store for 10 years.

After a discussion with the dealer, a new ECM was supplied, communication was restored and all was well.

The morale of the story is: Just because it's new does not mean it's OK. Continue to test even when new parts are fitted.

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