Page 95 of 436

TEST TC-20ACONTINUED - REPAIRING - BRAKE SWITCH PLAUSIBILITY WITH REDUNDANT
CONTACT
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
TEST TC-20A KEY OFF.
CONTINUED FROM DISCONNECT THE
THE PREVIOUS BRAKE LAMP SWITCH
PAGE. HARNESS
CONNECTOR.**
USING A VOLTMETER,
PROBE BRAKE SWITCH IS THE VOLTAGE NO REPAIR OPEN FUSED
HARNESS CONNECTOR ABOVE 9.0 VOLTS? BATTERY SUPPLY
CAVITY 6. CIRCUIT.*
FIG.1
YES
CONNECT A JUMPER
WIRE ACROSS THE DID THE DRB CHANGE YES ADJUST OR REPLACE
BRAKE LAMP FROM "RELEASED" TO THE BRAKE LAMP
HARNESS CONNECTOR "PRESSED"? SWITCH.*
CAV 5 AND 6. FIG.1
NO
KEY ON. USING A AT THE BRAKE LAMP REPAIR THE PRIMARY
VOLTMETER, MEASURE SWITCH HARNESS IS THE VOLTAGE YES BRAKE LAMP SWITCH
THE PRIMARY SWITCH CONNECTOR CAVITY 5. ABOVE 1.0 VOLT? SIGNAL CIRCUIT FOR
SIGNAL VOLTAGE... A SHORT TO
FIG.1 VOLTAGE.*
NO
KEY OFF. USING AN OHMMETER, REPAIR THE OPEN
DISCONNECT THE ECM MEASURE RESISTANCE IS THE RESISTANCE NO PRIMARY BRAKE LAMP
HARNESS OF THE PRIMARY BRAKE BELOW 5.0 OHMS? SWITCH SIGNAL
CONNECTORS.** LAMP SWITCH SIGNAL CIRCUIT.*
CIRCUIT. FIG.2
YES
REPLACE THE ENGINE
CONTROL MODULE.* SW
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Page 241 of 436

TEST TC-74ACONTINUED - REPAIRING - EMERGENCY STOP PLAUSIBILITY IN AFTER-RUN
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
TEST TC-74A KEY OFF.
CONTINUED FROM DISCONNECT THE REMOVE THE DIESEL
THE PREVIOUS FUEL PUMP AND ECM POWER RELAY.**
PAGE. HARNESS
CONNECTORS.**
WITH A JUMPER WIRE, KEY ON. USING A REPAIR THE FUEL
CONNECT DIESEL POWER VOLTMETER, MEASURE IS THE VOLTAGE YES SHUTDOWN SOLENOID
RELAY CONN. CAVITIES THE FUEL SHUTDOWN ABOVE 1.0 VOLT? CONTROL CIRCUIT
30 AND 87 (IN PDC). SOL CONTROL CKT. FOR A SHORT TO
FIG.1 FIG.2 VOLTAGE.*
NO
RECONNECT THE
ENGINE CONTROL KEY ON. USING DRB
MODULE HARNESS ACTUATE THE "FUEL
CONNECTORS. SHUT-OFF SOL."
WITH THE DRB FUEL PUMP HARNESS DOES VOLTMETER
ACTUATING THE CONNECTOR CAVITY 6. CHANGE FROM YES REPLACE FUEL PUMP
SOLENOID, USE A BATTERY VOLTAGE TO ASSEMBLY.*
VOLTMETER TO BELOW 1.0 VOLT?
PROBE... FIG.2
NO
NOTE: BEFORE
REPLACING 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 245 of 436

TEST TC-75ACONTINUED - REPAIRING - REDUNDANT EMERGENCY STOP POWERSTAGE
DEFECTIVE
*Perform Verification TEST VER-2A. **Check connectors - Clean / repair as necessary.
TEST TC-75A KEY OFF.
CONTINUED FROM DISCONNECT THE
THE PREVIOUS FUEL PUMP AND ECM
PAGE. HARNESS
CONNECTORS.**
MEASURE THE
USE AN OHMMETER IN RESISTANCE OF THE IS THE RESISTANCE NO REPAIR OPEN FUEL
THE FOLLOWING FUEL SHUTDOWN BELOW 5.0 OHMS? SHUTDOWN SOLENOID
STEPS. SOLENOID CONTROL CONTROL CIRCUIT.*
CIRCUIT. FIG.1
YES
MEASURE THEREPAIR THE FUEL
RESISTANCE OF THE IS THE RESISTANCE YES SHUTDOWN SOLENOID
FUEL SHUTDOWN SOL. BELOW 5.0 OHMS? CIRCUIT FOR A
CONTROL CIRCUIT TO SHORT TO GROUND.*
GROUND. FIG.2
NO
RECONNECT THE
ENGINE CONTROL KEY ON. USING DRB
MODULE HARNESS ACTUATE THE "FUEL
CONNECTORS. SHUT-OFF SOL."
WITH THE DRB FUEL PUMP HARNESS DOES VOLTMETER
ACTUATING THE CONNECTOR CAVITY 6. CHANGE FROM YES REPLACE FUEL PUMP
SOLENOID, USE A BATTERY VOLTAGE TO ASSEMBLY.*
VOLTMETER TO BELOW 1.0 VOLT?
PROBE... FIG.2
NO
NOTE: BEFORE
REPLACING ECM, DID FUEL INJECTION YES REPLACE THE ENGINE
PERFORM TEST NTC-3A PUMP PASS TEST CONTROL MODULE.*
TO CHECK INTERNAL NTC-3A?
FUEL PUMP CIRCUITRY.
NO
REPLACE THE FUEL
INJECTION PUMP
ASSEMBLY.*
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Page 387 of 436

TEST SC-3ACONTINUED - CHECKING SPEED CONTROL OPERATION
*Perform Verification TEST VER-3A. **Check connectors - Clean / repair as necessary.
TEST SC-3A KEY OFF.
CONTINUED FROM
THE PREVIOUS DISCONNECT THE BRAKE
PAGE. LAMP SWITCH HARNESS
CONNECTOR.**
USING A VOLTMETER, REPAIR THE BRAKE
PROBE BRAKE LAMP IS THE VOLTAGE NO LAMP SWITCH FUSED
SWITCH HARNESS ABOVE 9.0 VOLTS? BATTERY SUPPLY
CONNECTOR CAVITY 6. CIRCUIT FOR AN
FIG.1 OPEN.*
YES
CONNECT A JUMPER DOES THE DRB
BETWEEN BRAKE LAMP DISPLAY CHANGE YES ADJUST OR REPLACE
SWITCH HARNESS TURN IGNITION ON. FROM "RELEASED" TO THE BRAKE LAMP
CONNECTOR CAVITIES "PRESSED"? SWITCH.*
5 AND 6. FIG.1
NO
REMOVE THE JUMPER. AT THE BRAKE LAMP REPAIR THE PRIMARY
USING A VOLTMETER, SWITCH HARNESS IS THE VOLTAGE NO BRAKE SWITCH
MEASURE THE CONNECTOR CAVITY 5. BELOW 1.0 VOLT? SIGNAL CIRCUIT FOR
PRIMARY SWITCH A SHORT TO
SIGNAL CIRCUIT... FIG.1 VOLTAGE.*
YES
KEY OFF. USING AN OHMMETER, REPAIR THE PRIMARY
MEASURE RESISTANCE IS THE RESISTANCE NO BRAKE SWITCH
DISCONNECT THE ECM OF THE PRIMARY BRAKE BELOW 5.0 OHMS? SIGNAL CIRCUIT FOR
HARNESS SW SIGNAL CKT. AN OPEN.*
CONNECTORS.** FIG.2
YES
REPLACE THE ENGINE
CONTROL MODULE.*
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