Engine Wiring Harness

Main Page >> Wiring, Fuse Boxes and Relay Diagrams >> Engine Wiring Harness

Change language
Last update 07-04-2024

^{Figure 1 - Factory original wire hardness for the engine (see wiring diagrams manual, page 113)}

After removing all electrical wiring including CAN communication from a 2001 Volvo S60 and after cleaning it all and removing all protective plastic it was possible to understand how wiring is connected in a P2 Volvo, in particular how it connects on the engine bay to the ECU.

^{Figure 1 - Photo with all wiring installed on the engine bay of a Volvo P2 (Petrol) with the Relay box, the ETM , the ECU and a few sensors connected}

The first immediate conclusion was all high-power electrical wiring packed together with all other wires including sensors and CAN communications. This is well known to cause interference and even errors in both communications and also on sensor values measured by the ECU. In summary, the installation on the engine bay needs to change so high-power wires are installed apart from all other wiring to avoid unnecessary interference.

Upgrade to Shielded Wiring

Another option is to replace all sensor wires with only 4 wires in total capable of sensing each individual sensor value to the ECU located on the right side corner of the engine bay. I've pre-selected the RG 178 coaxial cable, suited for GHz electrical signal wrapped inside a heat-resistant protective sleeve for increased durability. This will require purposely designed hardware electronics capable of doing sensor measurement translation and sending it to the ECU. This can be achieved with an ESP32 C3 microcontroller and an I2C Compatible Dual Bidirectional Bus Buffer, for instance, the P82B96 installed along the new wiring near each individual sensor.

Upgrade Ignition and Injectors Wiring

Another point of failure is located in the engine, the wires for the ignition and the injectors, constantly under high temperatures during engine operation.