TM-9-2320-272-23-2

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 2 OF 5

SEPTEMBER 2012

TM-9-2320-272-23-2 - Page 232 of 1417

FIELD MAINTENANCE

ABS - CODE ISO1 91 (ABS VOLTAGE BELOW 8.0 VOLTS)

INITIAL SETUP:

Tools and Special Tools

Tool Kit, General Mechanic's: Automotive

(Volume 5, WP

0826, Table 1, Item 56)

ABS Diagnostic Info Centre (TM 9-2320-272-10)

Multimeter

(Volume 5, WP

0826, Table 1, Item 34)

Test Set, Electronic Systems

(Volume 5, WP

0826, Table 1, Item 51)

Personnel Required

(2)

References

Point to Point Schematics

References (cont.)

WP

0159

WP

0161

Volume 3, WP

0467

Equipment Condition

Vehicle parked and engine shut down.

(TM

9-2320-272-10)

TROUBLESHOOTING PROCEDURE

ABS - CODE ISO1 91 (ABS VOLTAGE BELOW 8.0 VOLTS)

STEP

1.

IS ABS POWER SUPPLY CIRCUIT OK?

NOTE

If power is coming from somewhere other than vehicle, make sure tester battery is fully

charged or voltage converter has adequate voltage (21.0 – 33.0 volts) and current

capacity (11 amps). Do not use a battery charger.

Check ABS power supply circuit, including ground wire "Y" connector, power cable "W" connector to wire

54, and both fuses, for damage, corrosion, splices, and sound connections. Refer to point to point

schematics.

CONDITION/INDICATION

IS ABS POWER SUPPLY CIRCUIT OK?

DECISION

YES - Notify supervisor. It is possible that another troubleshooting work package applies.

NO - Replace ABS wiring harness (Volume 3, WP

0467). Go to Step (2) to verify problem is solved.

TM 9-2320-272-23-2

0183

0183-1