TM-9-2320-272-23-1

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

TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5

SEPTEMBER 2012

TM-9-2320-272-23-1 - Page 1272 of 1313

FIELD MAINTENANCE

SOLID OVERSPEED WARNING LIGHT

INITIAL SETUP:

Tools and Special Tools

Tool Kit, General Mechanic's: Automotive

(Volume 5, WP

0826, Table 1, Item 56)

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.)

Volume 2, WP

0322

Volume 2, WP

0323

Volume 5, WP

0813

Equipment Condition

Vehicle parked and engine shut down.

(TM

9-2320-272-10)

TROUBLESHOOTING PROCEDURE

SOLID OVERSPEED WARNING LIGHT

NOTE

Conduct these malfunction tests if the system gives a solid overspeed warning light. This fault

is set because the ECU has seen 25 to 50 ignition cycles without sensing any speed input.

Move vehicle at greater than 5 MPH. If light does not go out, perform the following tests. This

procedure will check for a faulty Speed Signal Generator, Electronic Control Unit (ECU), and

CTIS wiring harness.

TM 9-2320-272-23-1

0151

0151-1