Pinpoint tests of electric auxiliary heater

NOTE:The additional electric heater with coolant heating only operates when the engine is running (D+ signal from the alternator) and provided that the alternator efficiency is adequate. The coolant temperature must not exceed 75°C and the outside temperature must be below 5°C.

B1: DETERMINING THE CONDITIONS UNDER WHICH A FAILURE OCCURRES

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

• Levels 1 and 2 of the auxiliary heater with coolant heating do not work?

→ Yes

Go to B2

→ No

Only level 1 doesn't work: Go to B5

Only level 2 doesn't work: Go to B14

B2: CHECKING CONTROL VOLTAGE IN THE AUXILIARY HEATER GLOW PLUG RELAY, LEVEL 1

1Enter the OFF position.

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

3Enter the ON position.

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

• Is battery voltage registered?

→ Yes

Go to B3

→ No

LOCATE and REPAIR the open in the 15-RH10 (Green/Red) circuit between the power hold relay and solder joint S117 using the wiring diagrams. CHECK for proper system operation.

B3: CHECKING THE SIGNAL FROM THE AIR INTAKE TEMPERATURE SENSOR

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

1Enter the OFF position.

2Connect the diagnostic tool.

3Enter the ON position.

4Check the air intake temperature signal using WDS.

• Is the air intake temperature signal OK, i.e. the indicated temperature value is probable?

→ Yes

Go to B4

→ No

For more information, refer to For more information, refer to Section 303-14.

B4: CHECKING THE GROUND CIRCUIT OF THE AUXILIARY ELECTRIC HEATER WITH COOLANT HEATING

1Enter the OFF position.

2Measure the resistance between the auxiliary electric coolant heater connector C965, circuit 15-RD22 (green/red), and ground.

• Resistance less than 1.1 ohms?

→ Yes

CHECK the powertrain control module (PCM) and REPLACE it if necessary. CHECK the system for proper operation.

→ No

CHECK the auxiliary electric coolant heater ground circuit, CLEAN the bulkhead thread(s) if necessary. CHECK the system for proper operation.

B5: CHECKING FUSE F24

1Enter the OFF position.

2CHECK Fuse F24 (BJB).

• Is the fuse good?

→ Yes

Go to B6

→ No

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

B6: CHECKING THE VOLTAGE IN FUSE F24

1Connect Fuse F24 (BJB).

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

• Is battery voltage registered?

→ Yes

Go to B7

→ No

RESTORE power to fuse F24 using the wiring diagrams. CHECK that the system is operating correctly.

B7: CHECKING CONTROL VOLTAGE IN THE AUXILIARY HEATER GLOW PLUG RELAY, LEVEL 1

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

2Enter the ON position.

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

• Is battery voltage registered?

→ Yes

Go to B8

→ No

LOCATE and REPAIR the open in circuit 15-RH23 (Green/Red) between the Aux Heater Glow Plug Relay, Stage 1 and solder joint S117 using the Wiring Diagrams. CHECK for proper system operation.

B8: CHECKING THE VOLTAGE IN THE AUXILIARY HEATER GLOW PLUG RELAY, LEVEL 1

1Enter the OFF position.

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

• Is battery voltage registered?

→ Yes

Go to B9

→ No

LOCATE and REPAIR the open in circuit 30-RH24 (red) between the booster heater glow plug relay, stage 1, and fuse F24 using the Wiring Diagrams. CHECK for proper system operation.

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

1Measure the resistance between glow plug relay connector C1002 pin 5, level 1, harness side and auxiliary electric heater with coolant heater connector C965, circuit 15-RD22 (green/red).

• Resistance less than 0.5 Ohm?

→ Yes

Go to B10

→ No

LOCATE and REPAIR the open in the electrical circuit between the Aux Heater Glow Plug Relay, Level 1 and the Electric Aux Heater with Coolant Heater using the Wiring Diagrams. CHECK for proper system operation.

B10: CHECKING THE ADDITIONAL HEATER WITH COOLANT HEATING

1Measure the resistance between the auxiliary heater with coolant heater connector C965, circuit 15-RD22 (green/red), and ground.

• Resistance less than 1.1 ohms?

→ Yes

Go to B11

→ No

REPLACE the auxiliary heater with coolant heating. CHECK the system for proper operation.

B11: CHECKING THE AUXILIARY HEATER GLOW PLUG RELAY, LEVEL 1

1Check the auxiliary heater glow plug relay, level 1, in accordance with the component tests described at the end of this section.

• Aux 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 the auxiliary heater glow plug relay, level 1. CHECK the system for proper operation.

B12: CHECK CIRCUIT BETWEEN PCM AND AUXILIARY HEATER GLOW PLUG RELAY, LEVEL 1 FOR OPEN

1Disconnect C415 PCM.

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

• Resistance less than 2 ohms?

→ Yes

CHECK the PCM and REPLACE it if necessary. CHECK the system is operating correctly.

→ No

LOCATE and REPAIR the open in the circuit between the PCM and the Supplemental Heater Glow Plug Relay, Level 1 using the Wiring Diagrams. CHECK for proper system operation.

B13: CHECK CIRCUIT BETWEEN PCM AND AUXILIARY HEATER GLOW PLUG RELAY, LEVEL 1 FOR OPEN

1Disconnect C414 PCM.

2Measure the resistance between pin 1 of connector C1002 of the glow plug relay, level 2, wiring harness side and pin 61 of connector C414 of the PCM, circuit 31S-RH23 (BK/OG), wiring harness side.

• Resistance less than 2 ohms?

→ Yes

CHECK the PCM and REPLACE it if necessary. CHECK the system is operating correctly.

→ No

LOCATE and REPAIR the open in the circuit between the PCM and the Supplemental Heater Glow Plug Relay, Level 1 using the Wiring Diagrams. CHECK for proper system operation.

B14: CHECKING FUSE F3

1Enter the OFF position.

2CHECK Fuse F3 (BJB).

• Is the fuse good?

→ Yes

Go to B15

→ No

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

B15: CHECKING THE VOLTAGE IN FUSE F3

1Connect Fuse F3 (BJB).

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

• Is battery voltage registered?

→ Yes

Go to B16

→ No

RESTORE power to fuse F3 using the wiring diagrams. CHECK that the system is operating correctly.

B16: CHECKING CONTROL VOLTAGE IN THE AUXILIARY HEATER GLOW PLUG RELAY, LEVEL 2

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

2Enter the ON position.

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

• Is battery voltage registered?

→ Yes

Go to B17

→ No

LOCATE and REPAIR the open in circuit 15-RH25 (BK/GN) between the auxiliary heater glow plug relay, stage 2 and solder joint S117 using the Wiring Diagrams. CHECK for proper system operation.

B17: CHECKING THE VOLTAGE IN THE AUXILIARY HEATER GLOW PLUG RELAY, LEVEL 2

1Enter the OFF position.

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

• Is battery voltage registered?

→ Yes

Go to B18

→ No

LOCATE and REPAIR the open in circuit 30-RH26 (Red) between the Aux Heater Glow Plug Relay, Stage 2 and fuse F3 using the Wiring Diagrams. CHECK for proper system operation.

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

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

• Resistance less than 0.5 Ohm?

→ Yes

Go to B19

→ No

LOCATE and REPAIR the open in the electrical circuit between the Aux Heater Glow Plug Relay Level 2 and the Electric Aux Heater with Coolant Heater using the Wiring Diagrams. CHECK for proper system operation.

B19: CHECKING THE ADDITIONAL HEATER WITH COOLANT HEATING

1Measure the resistance between the auxiliary heater with coolant heater connector C966, circuit 15-RD23 (black/green), and ground.

• Resistance less than 0.8 ohms?

→ Yes

Go to B20

→ No

REPLACE the auxiliary heater with coolant heating. CHECK the system for proper operation.

B20: CHECKING THE AUXILIARY HEATER GLOW PLUG RELAY, LEVEL 2

1Check the auxiliary heater glow plug relay, level 2, in accordance with the component tests described 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 the auxiliary heater glow plug relay, level 2. CHECK the system for proper operation.

B21: CHECK CIRCUIT BETWEEN PCM AND AUXILIARY HEATER GLOW PLUG RELAY, LEVELS 2 FOR OPEN

1Disconnect C415 PCM.

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

• Resistance less than 2 ohms?

→ Yes

CHECK the PCM and REPLACE it if necessary. CHECK the system is operating correctly.

→ No

LOCATE and REPAIR the open in the circuit between the PCM and the Supplemental Heater Glow Plug Relay, Level 2 using the Wiring Diagrams. CHECK for proper system operation.

B22: CHECK CIRCUIT BETWEEN PCM AND AUXILIARY HEATER GLOW PLUG RELAY, LEVELS 2 FOR OPEN

1Disconnect C414 PCM.

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

• Resistance less than 2 ohms?

→ Yes

CHECK the PCM and REPLACE it if necessary. CHECK the system is operating correctly.

→ No

LOCATE and REPAIR the open in the circuit between the PCM and the Supplemental Heater Glow Plug Relay, Level 2 using the Wiring Diagrams. CHECK for proper system operation.