Checking supply

Check the supply to Combustion Preheater Module (CPM) #9 for Contact resistance and oxidation , or a loose connection as described in Loose connections (terminals) . Also check fuse 9 in the engine compartment.

Check the cable between #1 on the Ext-X relay (2/29) and #15 on the Combustion Preheater Module (CPM) for Contact resistance and oxidation , or for a loose connection as described in Loose connections (terminals) . Also check the relay (2/29), the supply to the relay and passenger compartment fuse 24.

Check that the ground lead is undamaged by checking the cable between additional heater #3 and the ground terminal.

Also check the intermediate connectors.

Other information: 

• To replace the relay, see Central electronic module (CEM), replacing .
• For other values, see Signal specification .

Remedy as necessary.

Fig 2: Identifying Connector Terminals

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 3: Identifying Ohmmeter

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 4: Identifying Connector Terminals

Courtesy of VOLVO CARS OF NORTH AMERICA.

Refer to Verification