Pinpoint tests for electric auxiliary heater

NOTE: Electric auxiliary heater with coolant heating only works when the engine is running (D+ signal from generator) and subject to appropriate generator efficiency. The coolant temperature must not exceed 75°C and the outside temperature must be below 5°C.

B1: DEFINING THE CONDITIONS UNDER WHICH A FAULT OCCUR

1 Check the operation of the additional electric heater with coolant heating.

• Auxiliary heater levels 1 and 2 not working with water heater?

→ Yes

Navigate to B2

→ No

Only level 1 does not work: Go to B5

Only level 2 doesn't work: Go to B14

B2: CHECK THE CONTROL VOLTAGE IN THE AUXILIARY HEATING PLUG RELAY LEVEL 1

1 Enter the OFF position.

2 Disconnect C1002 auxiliary heater glow plug relay, level 1 (BJB).

3 Drive the ON position.

4 Measure voltage between C1002 connector pin 1, auxiliary heater glow plug relay, level 1, circuit 15-RH23 (green-red), from the wiring harness side, and ground.

• Is battery voltage being recorded?

→ Yes

Go to B3

→ No

LOCATE and REPAIR open circuit 15-RH10 (green-red) between the power supply relay and solder joint S117, using the wiring diagrams. CHECK the system is working properly.

B3: INTAKE TEMPERATURE SENSOR CHECK

NOTE: The intake air temperature sensor is built into the mass air flow sensor.

1 Enter the OFF position.

2 Connect the diagnostic tool.

3 Drive the ON position.

4 Check the air intake temperature signal using WDS.

• Air intake temperature signal OK, ie. Is the indicated temperature value likely?

→ Yes

Go to B4

→ No

For more information, see For more information, see Section 303-14.

B4: ELECTRIC AUXILIARY HEATER WITH COOLANT HEATING ELECTRIC GROUND CIRCUIT CHECK

1 Enter the OFF position.

2 Measure the resistance between connector C965, electrical auxiliary heater with water heater, circuit 15-RD22 (green-red), and "mass".

• Is the resistance less than 1.1 ohms?

→ Yes

CHECK the powertrain control module (PCM) and REPLACE if necessary. CHECK the system is working properly.

→ No

CHECK the ground circuit of the additional electric heater with coolant heating, if necessary CLEAN the threaded connection (I) on the partition. CHECK the system is working properly.

B5: FUSE CHECK F24

1 Enter the OFF position.

2 CHECK Fuse F24 (BJB).

• Is the fuse good?

→ Yes

Go to B6

→ No

REPLACE fuse F24 (30 A). CHECK the system is working properly. If the fuse blows again, LOCATE and REPAIR the short to ground using the wiring diagrams.

B6: FUSE VOLTAGE CHECK F24

1 Connect Fuse F24 (BJB).

2 Check the voltage in the electrical circuit between fuse F24 (30 A) and "mass".

• Is battery voltage being recorded?

→ Yes

Go to B7

→ No

RESTORE power to fuse F24 using the wiring diagrams. CHECK the system is working properly.

B7: CHECK THE CONTROL VOLTAGE IN THE AUXILIARY HEATING PLUG RELAY, LEVEL 1

1 Disconnect C1002 auxiliary heater glow plug relay level 1 (BJB).

2 Drive the ON position.

3 Measure voltage between C1002 connector pin 1, auxiliary heater glow plug relay, level 1, circuit 15-RH23 (green-red), from the wiring harness side, and ground.

• Is battery voltage being recorded?

→ Yes

Go to B8

→ No

LOCATE and REPAIR open circuit 15-RH23 (green-red) between the auxiliary heater glow plug relay, level 1, and solder joint S117, using the wiring diagrams. CHECK the system is working properly.

B8: AUXILIARY HEATING PLUG RELAY VOLTAGE CHECK LEVEL 1

1 Enter the OFF position.

2 Measure the voltage between C1002 pin 3 of the auxiliary heater glow plug relay, level 1, circuit 30-RH24 (red), from the wiring harness side, and ground.

• Is battery voltage being recorded?

→ Yes

Go to B9

→ No

LOCATE and REPAIR open circuit 30-RH24 (red) between the auxiliary heater glow plug relay, level 1, and fuse F24, using the wiring diagrams. CHECK the system is working properly.

B9: CHECK THE ELECTRICAL CIRCUIT BETWEEN THE AUXILIARY HEATING PLUG RELAY LEVEL 1 AND THE AUXILIARY ELECTRIC HEATER WITH COOLANT HEATING FOR OPEN.

1 Measure the resistance between C1002 Glow Plug Relay Pin 5, Level 1, Harness Side, and C965 Electrical Auxiliary Heater with Water Heater Circuit 15-RD22 (green-red).

• Is the resistance less than 0.5 ohm?

→ Yes

Go to B10

→ No

LOCATE and REPAIR the open circuit between the auxiliary heater glow plug relay, level 1, and the heated water heater electric auxiliary heater using the wiring diagrams. CHECK the system is working properly.

B10: CHECK AUXILIARY HEATER WITH COOLANT HEAT

1 Measure the resistance between connector C965, auxiliary heater with water heater, circuit 15-RD22 (green-red), and "mass".

• Is the resistance less than 1.1 ohms?

→ Yes

Go to B11

→ No

REPLACE auxiliary heater with water heater. CHECK the system is working properly.

B11: AUXILIARY HEATING PLUG RELAY TEST LEVEL 1

1 Test the auxiliary heater glow plug relay, level 1, according to the item checks at the end of this section.

• Auxiliary heater glow plug relay level 1 OK?

→ Yes

Vehicles with 104-pin EEC: Go to B12

Vehicles with 121-pin EEC: Go to B13

→ No

REPLACE auxiliary heater glow plug relay level 1. CHECK system for proper operation.

B12: CHECK CIRCUIT BETWEEN PCM AND AUXILIARY HEATING PLUG RELAY LEVEL 1 FOR OPEN

1 Disconnect the C415 PCM.

2 Measure the resistance between C1002 connector pin 2 of auxiliary heater glow plug relay level 1 harness side and C415 PCM connector pin 98, circuit 31S-RH23 (black-orange), from the wiring harness side.

• Is the resistance less than 2 ohms?

→ Yes

CHECK PCM and REPLACE if necessary. CHECK the system is working properly.

→ No

LOCATE and REPAIR the open circuit between the PCM and the auxiliary heater glow plug relay level 1 using the wiring diagrams. CHECK the system is working properly.

B13: CHECK CIRCUIT BETWEEN PCM AND AUXILIARY HEATING PLUG RELAY LEVEL 1 FOR OPEN

1 Disconnect the C414 PCM.

2 Measure the resistance between C1002 connector pin 1 of the auxiliary heater glow plug relay, level 2, harness side, and C414 PCM connector pin 61, circuit 31S-RH23 (black-orange), from the wiring harness side.

• Is the resistance less than 2 ohms?

→ Yes

CHECK PCM and REPLACE if necessary. CHECK the system is working properly.

→ No

LOCATE and REPAIR the open circuit between the PCM and the auxiliary heater glow plug relay level 1 using the wiring diagrams. CHECK the system is working properly.

B14: FUSE CHECK F3

1 Enter the OFF position.

2CHECK Fuse F3 (BJB).

• Is the fuse good?

→ Yes

Go to B15

→ No

REPLACE fuse F3 (40 A). CHECK the system is working properly. If the fuse blows again, LOCATE and REPAIR the short to ground using the wiring diagrams.

B15: FUSE VOLTAGE TEST F3

1 Connect Fuse F3 (BJB).

2 Check the voltage in the electrical circuit between fuse F3 (40 A) and "mass".

• Is battery voltage being recorded?

→ Yes

Go to B16

→ No

RESTORE power to fuse F3 using the wiring diagrams. CHECK the system is working properly.

B16: CHECK THE CONTROL VOLTAGE IN THE AUXILIARY HEATING PLUG RELAY LEVEL 2

1 Disconnect C1010 auxiliary heater glow plug relay level 2 (BJB).

2 Drive the ON position.

3 Measure voltage between C1010 connector pin 1, auxiliary heater glow plug relay, level 2, circuit 15-RH25 (black and green), from the wiring harness side, and ground.

• Is battery voltage being recorded?

→ Yes

Go to B17

→ No

LOCATE and REPAIR open circuit 15-RH25 (black and green) between the auxiliary heater glow plug relay, level 2, and solder joint S117, using the wiring diagrams. CHECK the system is working properly.

B17: AUXILIARY HEATING PLUG RELAY VOLTAGE CHECK LEVEL 2

1 Enter the OFF position.

2 Measure voltage between C1010 connector pin 3, auxiliary heater glow plug relay, level 2, circuit 30-RH26 (red), from the wiring harness side, and ground.

• Is battery voltage being recorded?

→ Yes

Go to B18

→ No

LOCATE and REPAIR open circuit 30-RH26 (red) between the auxiliary heater glow plug relay, level 2, and fuse F3, using the wiring diagrams. CHECK the system is working properly.

B18: CHECK THE ELECTRICAL CIRCUIT BETWEEN THE AUXILIARY HEATING PLUG RELAY LEVEL 2 AND THE AUXILIARY ELECTRIC HEATER WITH COOLANT HEATING FOR OPEN.

1 Measure the resistance between C1010 connector pin 5 of the auxiliary heater glow plug relay, level 2, wiring harness side, and connector C967 of the electric auxiliary heater with coolant heating, wiring harness side.

• Is the resistance less than 0.5 ohm?

→ Yes

Go to B19

→ No

LOCATE and REPAIR the open circuit between the auxiliary heater glow plug relay, level 2, and the heated water heater electric auxiliary heater using the wiring diagrams. CHECK the system is working properly.

B19: CHECK AUXILIARY HEATER WITH COOLANT HEATING

1 Measure the resistance between connector C966 auxiliary heater with water heater, circuit 15-RD23 (black and green), and "mass".

• Is the resistance less than 0.8 ohm?

→ Yes

Go to B20

→ No

REPLACE auxiliary heater with water heater. CHECK the system is working properly.

B20: AUXILIARY HEATING PLUG RELAY TEST LEVEL 2

1 Test the auxiliary heater glow plug relay, level 2, according to the item checks at the end of this section.

• Auxiliary heater glow plug relay level 2 OK?

→ Yes

Vehicles with 104-pin EEC: Go to B21

Vehicles with 121-pin EEC: Go to B22

→ No

REPLACE auxiliary heater glow plug relay level 2. CHECK system for correct operation.

B21: CHECK CIRCUIT BETWEEN PCM AND AUXILIARY HEATER PLUG RELAY LEVEL 2 FOR OPEN

1 Disconnect the C415 PCM.

2 Measure the resistance between C1010 connector pin 2, auxiliary heater glow plug relay level 2, harness side, and C415 pin 75, circuit 31S-RH25 (black and green), from the wiring harness side.

• Is the resistance less than 2 ohms?

→ Yes

CHECK PCM and REPLACE if necessary. CHECK the system is working properly.

→ No

LOCATE and REPAIR the open circuit between the PCM and the auxiliary heater glow plug relay level 2 using the wiring diagrams. CHECK the system is working properly.

B22: CHECK CIRCUIT BETWEEN PCM AND AUXILIARY HEATING PLUG RELAY LEVEL 2 FOR OPEN

1 Disconnect the C414 PCM.

2 Measure the resistance between C1010 connector pin 2, auxiliary heater glow plug relay level 2, harness side, and C414 pin 62, circuit 31S-RH25 (black and green), from the wiring harness side.

• Is the resistance less than 2 ohms?

→ Yes

CHECK PCM and REPLACE if necessary. CHECK the system is working properly.

→ No

LOCATE and REPAIR the open circuit between the PCM and the auxiliary heater glow plug relay level 2 using the wiring diagrams. CHECK the system is working properly.