Dear volhunvo,

Hope you're well. According to the Volvo pocket data booklet - Cars (700,850,900): 1991-1996 (page 28), engine control unit (ECU) 0 280 000 936 (Volvo #3547779) was used only in '92-95 cars, with the B200F engine.

This Volvo publication also shows that ECM 0 280 000 949 (Volvo #6842289) was also used in '92-95 cars, with the B200F engine. This Volvo publication does not set forth what differences, if any, separate the -936 and -949 units.

If you need to replace the ECM (not often required) - and can't get a -936 unit - you might try a -949 unit. It could be that there's no major difference between the two.

Before replacing an ECU, alwyas disconnect the negative battery cable clamp from the negative battery terminal. Put the negative battery cable clamp in a plastic bag, to isolated it.

If your car's radio is the factory-installed unit, be sure you have the radio security code, before disconnecting the negative battery cable from the battery. Cutting power to the car triggers an anti-theft device in the radio.

If you do not have your car's radio security code, contact a Volvo dealer service department, and give them your car's Vehicle Identification Number (VIN). If the radio has been replaced with the same Volvo radio, you'll need a number on the radio itself. If that label is missing, the radio will "go dead" and can't be reactivated. If you have an aftermarket radio, the radio will come back on, when power is restored.

Hope this helps.

Yours faithfully,

Spook