Component Tests and General Diagnostics

Checking the supply voltage/ground terminal

Checking the supply voltage/ground terminal

Power Steering Control Module (PSCM)
Power Steering Control Module (PSCM) is supplied with voltage (30-feed) via a voltage input on the control module, as well as 15-feed via ignition to a voltage input on the control module.

Note! There is no cable harness to Power Steering Control Module (PSCM) for connecting the breakout box. Therefore, it is important that any measurements are performed very carefully to prevent short-circuits, damage to connectors, etc.

Power supply (30-supply)
Voltage input #B1 has +30-feed via a fuse from the battery. It will not be possible to activate the power steering function if there is an open-circuit.

Checking supply voltage (30-supply)
Check the voltage feed cable from the battery to Power Steering Control Module (PSCM) #B1 for open circuit, loose connection, contact resistance, and oxidation. Check the fuse. The voltage should be approx. the same as the battery voltage.

Note! In the event of a damaged fuse, check the circuit. Check for a short-circuit before replacing the fuse. Any damage to the cable insulation can also cause intermittent or permanent short-circuits.

Power supply from ignition switch (15-supply)
Voltage input #A1 has +15-feed via ignition and is fused in relay or fuse box engine compartment and in Central electronic module (CEM). It will not be possible to activate the power steering function if there is an open-circuit.

Checking the power supply from ignition switch (15-supply)
Check the voltage feed cable from the battery via the ignition to Power Steering Control Module (PSCM) #A1 for open circuit, loose connection, contact resistance, and oxidation. Check the fuse. The voltage should be approx. battery voltage at ignition on and Ulow at ignition off.

Ground terminal
Power Steering Control Module (PSCM) has a ground input. The ground input from the control module is power ground and is connected to the ground terminal in the car body. For more information on ground connections, see the relevant wiring diagram.

Checking ground terminal
Check the ground lead between the electrical power steering module (EPS) terminal #B2 and the ground terminal. Check for an open-circuit. Check for loose connections. Check for contact resistance. Check for oxidation.
Remedy as necessary.

Other information
- Checking wiring and terminals Checking Wiring and Terminals. Permanent Faults
- Signal specification Pinout Values and Diagnostic Parameters
- See the relevant wiring diagram for information about circuits and ground terminals in the bodywork.





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