Page 253 of 436
TEST TC-80AREPAIRING - SOLENOID VALVE CONTROLLER SHORT CIRCUIT
Perform TEST DTC Before Proceeding
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
KEY ON, READ CODES.
START TEST WITH THE DRB, DOES THE DRB DISPLAY YES CONTINUE TEST
TC-80A. ERASE CODES. TURN "SOLENOID VALVE TC-80A ON THE
IGNITION OFF. CONTROLLER SHORT NEXT PAGE.
CIRCUIT"?
NO
USE THE SCHEMATIC AS DOES THE DRB REPAIR THE HARNESS
A GUIDE AND WIGGLE MONITOR THE DRB DISPLAY "SOLENOID YES OR CONNECTOR THAT
THE SOLENOID VALVE DISPLAY. VALVE CONTROLLER CAUSED THE CODE TO
CONNECTOR & HARNESS. SHORT CIRCUIT"? SET.*
FIG.1
NO
AT THIS TIME, THE USING THE
CONDITION REQUIRED SCHEMATIC AS A WERE ANY PROBLEMS YES REPAIR AS
TO SET THE CODE IS GUIDE, INSPECT THE FOUND? NECESSARY.*
NOT PRESENT. WIRING AND
FIG.2 CONNECTORS.
NO
REFER TO GENERAL
INFORMATION 3.3.2 YES
FOR ADDITIONAL TEST COMPLETE.*
INFORMATION ON
INTERMITTENT CODES.
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Page 255 of 436

TEST TC-80ACONTINUED - REPAIRING - SOLENOID VALVE CONTROLLER SHORT CIRCUIT
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
KEY OFF. KEY ON. ERASE CODES.
TEST TC-80A DISCONNECT THE DOES THE DRB DISPLAY YES REPLACE THE FUEL
CONTINUED FROM FUEL PUMP ASSEMBLY "FUEL TIMING PUMP ASSEMBLY.*
PREVIOUS PAGE. CONNECTOR.** SOLENOID CONTROLLER
OPEN CIRCUIT"?
NO
KEY OFF.
DISCONNECT THE ECM REMOVE THE DIESEL
HARNESS POWER RELAY.
CONNECTORS.**
WITH A JUMPER WIRE, KEY ON. USING A REPAIR THE FUEL
CONNECT DIESEL POWER VOLTMETER MEASURE IS THE VOLTAGE YES TIMING SOLENOID
RELAY CONN. CAVITIES THE FUEL TIMING ABOVE 1.0 VOLTS? CONTROL CIRCUIT
30 AND 87 (IN PDC). SOLENOID CONTROL FOR A SHORT TO
FIG.1 CKT. FIG.2 VOLTAGE.*
NO
NOTE: BEFORE
REPLACING THE ECM, DID THE FUEL YES REPLACE THE ENGINE
PERFORM TEST NTC-3A INJECTION PUMP CONTROL MODULE.*
TO CHECK INTERNAL PASS TEST NTC-3A?
FUEL PUMP CIRCUITRY.
NO
REPLACE THE FUEL
INJECTION PUMP
ASSEMBLY.*
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Page 259 of 436

TEST TC-81ACONTINUED - REPAIRING - TEMPERATURE OF ENGINE COOLANT SRC HIGH
EXCEEDED
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
TEST TC-81A KEY OFF.
CONTINUED FROM DISCONNECT THE ECT
THE PREVIOUS SENSOR HARNESS
PAGE. CONNECTOR.**
KEY ON. MEASURE THE ECT REPAIR THE ECT
SIGNAL CIRCUIT. IS THE VOLTAGE YES SENSOR SIGNAL CKT
USE A VOLTMETER IN ABOVE 5.5 VOLTS? FOR A SHORT TO
THE FOLLOWINGVOLTAGE.* IF OK,
STEP. FIG.1 REPLACE THE ECM.*
NO
CONNECT A JUMPER WITH THE DRB, READ REPLACE THE ENGINE
BETWEEN THE ECT THE ENGINE COOLANT IS THE VOLTAGE YES COOLANT
SENSOR SIGNAL AND TEMPERATURE SENSOR BELOW 1.0 VOLT? TEMPERATURE
SENSOR GROUND CKT. VOLTAGE. SENSOR.*
FIG.1
NO
MOVE THE JUMPER WITH THE DRB, READ
WIRE FROM THE THE ENGINE COOLANT IS THE VOLTAGE YES REPAIR THE OPEN
SENSOR GROUND TO TEMPERATURE SENSOR BELOW 1.0 VOLT? SENSOR GROUND
AN ENGINE GROUND. VOLTAGE. CIRCUIT.*
FIG.1
NO
KEY OFF.
DISCONNECT THE ECM USE AN OHMMETER IN
HARNESS THE FOLLOWING
CONNECTORS.** STEP.
MEASURE THE ENGINE
COOLANT TEMEPERATURE IS THE RESISTANCE YES REPLACE THE ENGINE
SENSOR SIGNAL BELOW 5.0 OHMS? CONTROL MODULE.*
CIRCUIT.
FIG.2
NO
REPAIR THE OPEN
ENGINE COOLANT
TEMPERATURE SENSOR
SIGNAL CIRCUIT.*
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Page 263 of 436

TEST TC-82ACONTINUED - REPAIRING - TEMPERATURE OF ENGINE COOLANT SRC LOW
EXCEEDED
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
TEST TC-82A DISCONNECT THE
CONTINUED FROM ENGINE COOLANT
THE PREVIOUS TEMPERATURE SENSOR
PAGE. HARNESS
CONNECTOR.**
WITH THE DRB, READ IS THE ENGINE REPLACE THE ENGINE
ENGINE COOLANT COOLANT YES COOLANT
TEMPERATURE SENSOR TEMPERATURE SENSOR TEMPERATURE
VOLTAGE. VOLTAGE ABOVE 4.0 SENSOR.*
VOLTS?
NO
KEY OFF. USING AN OHMMETER, REPAIR THE SENSOR
DISCONNECT THE ECM MEASURE BETWEEN THE IS THE RESISTANCE YES SIGNAL CIRCUIT FOR
HARNESS SENSOR SIGNAL BELOW 5.0 OHMS? A SHORT TO
CONNECTORS.** CIRCUIT AND GROUND. GROUND.*
FIG.1
NO
WITH AN OHMMETER SENSOR SIGNAL REPAIR THE ECT
MEASURE THE CIRCUIT AND THE IS THE RESISTANCE YES SENSOR SIGNAL
RESISTANCE BETWEEN SENSOR GROUND BELOW 5.0 OHMS? CIRCUIT FOR A SHORT
THE ENGINE COOLANT CIRCUIT. TO THE ECT SENSOR
TEMPERATURE... FIG.1 GROUND CIRCUIT.*
NO
REPLACE THE ENGINE
CONTROL MODULE.*
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Page 265 of 436
TEST TC-84AREPAIRING - TERMINAL 15 PLAUSIBILITY AFTER START-UP
Perform TEST DTC Before Proceeding
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
START TEST WITH THE DRB,
TC-84A. ERASE CODES.
CYCLE THE IGNITION
ON AND OFF SEVERAL WITH THE IGNITION DOES THE DRB YES CONTINUE TEST
TIMES, PAUSING FOR ON ENGINE OFF, DISPLAY "TERMINAL TC-84A ON THE
TEN SECONDS AT KEY READ CODES. 15 PLAUSIBILITY"? NEXT PAGE.
ON AND OFF.
NO
AT THIS TIME THE REVIEW THE CIRCUIT
CONDITION FOR DESCRIPTION FOR A WERE ANY PROBLEMS YES REPAIR AS
SETTING THE CODE PROPER UNDERSTANDING FOUND? NECESSARY.*
IS NOT PRESENT. OF THIS CODE. CHECK
FIG. 1 FOR PROBLEMS.
NO
TEST COMPLETE.*
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Page 267 of 436

TEST TC-84ACONTINUED - REPAIRING - TERMINAL 15 PLAUSIBILITY AFTER START-UP
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
TEST TC-84A KEY OFF.
CONTINUED FROM DISCONNECT THE ECM
THE PREVIOUS HARNESS
PAGE. CONNECTORS.**
USING A VOLTMETER, NOTE: BE SURE TO IS THE VOLTAGE
MEASURE ALL ECM EXCLUDE CAVITIES ABOVE 2.0 VOLTS NO REPLACE THE ENGINE
HARNESS CONNECTOR 30,33,45 AND 51 FOR ANY OF THE CONTROL MODULE.*
CAVITIES EXCEPT FROM THIS STEP. MEASUREMENTS?
30,33,45 AND 51.
YES
IS VOLTAGE PRESENT REPAIR SHORT TO
AT ECM HARNESS NO VOLTAGE ON THE
CONNECTOR CAVITIES CIRCUIT THAT
2 OR 28? MEASURED ABOVE 2.0
VOLTS.*
YES
USING A VOLTMETER, REPAIR THE SHORT
REMOVE THE DIESEL MEASURE ECM HARNESS IS THE VOLTAGE YES TO VOLTAGE ON THE
POWER RELAY.** CONNECTOR CAVITY 2. ABOVE 2.0 VOLTS? DIESEL POWER RELAY
OUTPUT CKT.*
FIG.1
NO
TURN IGNITION OFF. THE DIESEL POWER REPAIR THE SHORT
USING AN OHMMETER, RELAY CONTROL CKT. IS THE RESISTANCE YES TO GROUND ON THE
MEASURE BETWEEN AT THE PDC. BELOW 5.0 OHMS? DIESEL POWER RELAY
GROUND AND... CONTROL CKT.*
FIG.2
NO
REPLACE THE DIESEL
POWER RELAY.*
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Page 279 of 436
TEST TC-91ACONTINUED - REPAIRING - VEHICLE SPEED SENSOR TROUBLE CODES
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
KEY OFF.
TEST TC-91A
CONTINUED FROM DISCONNECT THE VSS
PREVIOUS PAGE. HARNESS
CONNECTOR.**
USING A VOLTMETER, REPAIR THE
MEASURE THE FUSED IS THE VOLTAGE NO IGNITION SWITCH
TURN IGNITION ON. IGNITION SWITCH ABOVE 10.0 VOLTS? OUTPUT CIRCUIT FOR
OUTPUT CKT. AN OPEN OR SHORT
FIG.1 TO GROUND.*
YES
USING A VOLTMETER,
MEASURE THE VSS IS THE VOLTAGE NO CONTINUE TEST
SIGNAL CIRCUIT. BETWEEN TC-91A ON THE
4.0 AND 6.0 VOLTS? NEXT PAGE.
FIG.1
YES
KEY OFF. USING AN OHMMETER,
MEASURE RESISTANCE IS THE RESISTANCE NO REPAIR THE OPEN
DISCONNECT THE ECM OF SENSOR GROUND CKT BELOW 5.0 OHMS? SENSOR GROUND
HARNESS BETWEEN ECM AND VSS. CIRCUIT.*
CONNECTORS.** FIG.2
YES
PERFORM TEST
TC-91B.
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Page 281 of 436

TEST TC-91ACONTINUED - REPAIRING - VEHICLE SPEED SENSOR TROUBLE CODES
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
TEST TC-91A
CONTINUED FROM IS THE VOLTAGE YES CONTINUE TEST
THE PREVIOUS ABOVE 6.0 VOLTS IN TC-91A ON THE
PAGE. THE PREVIOUS STEP? NEXT PAGE.
NO
KEY OFF. KEY ON.
USING A VOLTMETER, IS THE VOLTAGE YES REPLACE THE BODY
DISCONNECT THE BCM MEASURE THE VSS BETWEEN CONTROL MODULE.*
"B" HARNESS SIGNAL CKT. 4.0 AND 6.0 VOLTS?
CONNECTOR.** FIG.1
NO
KEY OFF. USING AN OHMMETER, REPAIR THE VSS
MEASURE BETWEEN IS THE RESISTANCE YES SIGNAL CIRCUIT FOR
DISCONNECT THE ECM VSS SIGNAL CKT AND BELOW 5.0 OHMS? A SHORT TO SENSOR
HARNESS SENSOR GROUND CKT. GROUND CIRCUIT.*
CONNECTORS.** FIG.1
NO
USING AN OHMMETER, REPAIR THE VSS
MEASURE BETWEEN IS THE RESISTANCE YES SIGNAL CIRCUIT FOR
VSS SIGNAL CKT AND BELOW 5.0 OHMS? A SHORT TO
GROUND. GROUND.*
FIG.1
NO
USING AN OHMMETER,
MEASURE THE THE VSS SENSOR AND IS THE RESISTANCE NO REPAIR THE OPEN
RESISTANCE OF THE THE ECM. BELOW 5.0 OHMS? VSS SIGNAL
VSS SIGNAL CKTCIRCUIT.*
BETWEEN... FIG.2
YES
REPLACE THE ENGINE
CONTROL MODULE.*
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