P187 4 - VERNIER CONTROL INPUT FAILED HIGH (HIGH VOLTAGE) (ALSO CALLED VARIABLE SPEED GOVERNOR

TM 9-2320-364-20-1

2-14. DDEC III/IV TROUBLESHOOTING (CONT).

Section IV. TROUBLESHOOTING CHARTS (Cont.)

E. FLASH CODE:

J1587 CODE:

P187 3 -

VERNIER CONTROL INPUT FAILED HIGH (HIGH VOLTAGE)

(ALSO CALLED VARIABLE SPEED GOVERNOR - VSG)

NOTE - This chart is only to be used if:

1) All basic mechanical checks and physical inspections have been performed with no problem found; and,

2) Diagnosis of DDEC III/IV was started at step START-1, pg 2-539, and you have now been referred here.

STEP/SEQUENCE

RESULT

WHAT TO DO NEXT

12-1

Multiple Code Check

Were there any other active codes

No other active codes.

Go to 12-2.

besides Code 187/3?

Yes, either code

Go to VEH5V-1 , page 2-767.

91/3 or 4.

Yes - but none

Go to 12-2.

of the above.

12-2

Sensor Check

Turn ignition off.

Any codes

Go to 12-3.

Unplug the vernier control from

except Code 187/3.

vernier control harness connector.

Turn ignition on.

Code 187/3 (and any

Go to 12-5.

Read active codes.

other codes).

12-3

Return Circuit Check

Transmission in neutral.

Less than or

Go to 12-4.

Turn ignition off.

equal to 5 ohms.

Install a jumper wire between pin

A and pin B of the vernier control

Greater than

Return line (ckt #952) is open.

connector.

5 ohms or open.

Repair open. Then go to 12-30.

Disconnect the vehicle harness

connector at the ECM.

Turn ignition on.

Push ENGINE HIGH IDLE LATCH

switch to LATCH and release.

Read resistance between sockets

C3 (952) and D1 (510) on the

vehicle harness connector.

12-4

Check Vernier

Control Connectors

Inspect terminals at the vernier

Terminals and

Replace vernier control

control connectors (sensor side

connectors are okay.

(para 7-100). Then go to 12-30.

and harness side) for damage;

bent, corroded, and unseated

pins or sockets.

Problem found.

Repair terminals/connectors

(para 7-101). Then go to 12-30.

2-625