Experiencing starting problems with your Lamborghini Huracan can be frustrating. Often, these issues can stem from problems within the engine control module (ECM) system or the starter relays. This guide will walk you through initial steps to diagnose these potential culprits, focusing on verifying ECM communication and examining the starter relay circuit in your Huracan.
To begin, it’s crucial to ensure your Huracan’s ECMs are online and communicating effectively with other control units. For any control module to function correctly, it requires consistent power, a solid ground connection, and a working communication link. Let’s examine the specifics for ECM 1 (J623) in your Lamborghini Huracan as an example*:
- Power for ECM 1: Check Pins 3, 5, and 6 (Red/Yellow wire, D182)-Connection 3 (87a)
- Ground for ECM 1: Verify Pins 1, 2, and 4 (Brown wire, 708)-Earth point 2 on the rear right longitudinal member
- CAN-Bus Communication: Inspect Pins 77/80 for CAN Low and Pins 60/79 for CAN High
Example image of ECM connections for illustrative purposes.
*While the following information is believed to be accurate, it is not guaranteed to be 100% correct. Always refer to the Official Factory Repair manuals for definitive guidance.
In a standard Lamborghini Huracan setup, two starter relays, J53-Starter Motor Relay 1 and J695-Starter Motor Relay 2, are managed by the J623 ECM to activate the starter.
Both starter relays are powered by the (D52)-15 Power connection. This 15-power source feeds into terminal 30 of the J53 relay. When J53 is activated, power flows to the J695 relay. Subsequently, when J695 is activated, it delivers power to the starter motor.
The J53 relay is triggered when the ECM terminal T91/70 (Brown/Green wire) sends a ground signal. Similarly, the J695 relay is activated by a ground signal from ECM terminal T91/52 (Brown/Red wire).
To troubleshoot, check for these ground signals from the ECM at relays J53 and J695 when starting is attempted. These relays are located within the electronics box in the right engine compartment (specifically, the 645 relays closest to the coolant reservoir). For testing purposes, you could also manually ground the two starter relay coils with the ignition on to see if the starter engages.
Depiction of a typical starter relay location in an engine compartment.
Keep in mind that the above information pertains to the stock ECM setup. If your Huracan has a stand-alone ECM, the wiring and control of the starter relays might differ. However, with the stock ECM, the information provided should be a useful starting point.
Furthermore, utilizing a diagnostic tool like VCDS, when you establish communication with the ECM, you can use “Advanced Measuring Value” to monitor the “Status of starter activation.” This provides feedback from the 50-Power output of the J53 relay to the starter relay, aiding in pinpointing issues within the circuit.
This information is intended to assist in your diagnostic process. Remember to consult official Lamborghini repair manuals and consider seeking professional help for complex issues.
