Fault code: EMS 4689 SCANIA

Error identification:

It has not taken as long as expected for the control unit to build up the current in the solenoid valve. The control unit uses the battery voltage and the engine temperature to calculate how long it should take to build up the current.

Cause:

The fault can be due to solenoid valve resistance being too low.

If fault code 4691 has been generated at the same time, it is probably due to a short circuit in the solenoid valve or the electrical cables. A short circuit may also have occurred between the rocker cover and one of the cable terminals on the solenoid valve.

Notes:

The control unit attempts to get the engine to continue using the faulty cylinder as long as possible. Certain types of short circuits can affect multiple cylinders. Fault codes will be generated for those cylinders affected by the short circuit. However, there may be instances where another cylinder is short circuited without generating any fault codes.

If fault codes are generated for more than one cylinder, maximum engine torque will be reduced by approx. 30%.

Action:

Check the circuit components, harness-to-harness connectors and electrical cables.

Check the resistance of the solenoid valve. Resistance should be 0.4 – 0.6 ohms. Also check the resistance between the solenoid valve connection and the engine. If the resistance is below 100 ohms, there is probably a short circuit.

Clear the fault code memory.

If the fault remains, first renew the unit injector and if necessary the control unit.