34
1st . Blink
Code
12
Location:
Miscellaneous
Troubleshooting Diagnostic Trouble Codes: Miscellaneous
2nd .
Blink
Code
Diagnostic Trouble
Code Description
Repair Information
1
Stop Lamp Switch Not
Detected
ECU has not detected the presence of the stop lamp switch since ignition power was
applied (note that stop lamp switch input may be applied to the Bendix
®
EC-60
™
controller
using either hardwire input or J1939). Apply and release service brake. Check for brake
switch input into ECU (see system wiring schematic). With service brake released, check
for presence of the stop lamp bulb. With service brake applied, verify system voltage is
now present at the stop lamp switch input to the ECU. Check for damaged wiring between
ECU, stop lamp switch and bulb. Check for corroded or damaged connectors. Check
for damaged or reversed J1939 wiring. Check for corroded or damaged connectors on
J1939 link. Verify presence of engine ECU on the J1939 link. Verify ECU configuration.
2
Stop Lamp Switch
Defective
Apply and release service brake. Check for brake switch input into ECU (see system
wiring schematic). With service brake released, check for presence of the stop lamp bulb.
With service brake applied, verify system voltage is now present at the stop lamp switch
input to the ECU. Check for damaged wiring between ECU, stop lamp switch and bulb.
Check for corroded or damaged connectors. Check for damaged or reversed J1939
wiring. Check for corroded or damaged connectors on J1939 link. Verify presence of
engine ECU on the J1939 link. Verify ECU configuration.
3
ATC Disabled or
Dynamometer Test
Mode Active
ATC is disabled. ECU has been placed in the Dynamometer Test Mode by either the
diagnostic blink code switch or a hand-held or PC-based diagnostic tool. Clear DTCs to
exit Dynamometer Test Mode.
4
Retarder Relay or HSA
Lamp Open Circuit or
Shorted to Ground
Verify vehicle contains a retarder relay or Hill Start Assist (HSA) lamp. Verify ECU
configuration. Check wiring between ECU and retarder relay or HSA lamp. Verify no
continuity between retarder disable output or HSA lamp output of Bendix EC-60 controller
and ground. Verify condition and wiring of the retarder relay or HSA lamp.
5
Retarder Relay or HSA
Lamp Circuit Shorted to
Voltage
Check wiring between ECU and retarder relay or HSA lamp. Verify no continuity between
retarder disable output or HSA lamp output of Bendix EC-60 controller and voltage. Verify
condition and wiring of the retarder relay or HSA lamp.
6
ABS Indicator Lamp
Circuit DTC
Check operation of diagnostic blink code switch. Check wiring of diagnostic blink code
switch (verify ABS wire is not grounded where used) and ABS Indicator Lamp. Verify
ABS Indicator Lamp ground input. On some vehicles with multi-plex dashes, the ground
wire may not be present
- see ECU 19 DTC.
7
PMV Common Shorted
to Ground
Verify no continuity between the Release, Hold and CMN of all PMVs, TCV, HSA, Diff Lock
Solenoid and ground. Check for corroded/damaged wiring or connectors between the
ECU and CMN of all PMVs, TCV, and Diff Lock Solenoid. See extended troubleshooting
for this code in Appendix A.
8
PMV Common Shorted
to Voltage
Verify no continuity between the Release, Hold and CMN of all PMVs, TCV, HSA, Diff
Lock Solenoid and voltage. Check for corroded/damaged wiring or connectors between
the ECU and CMN of all PMVs, TCV, and Diff Lock Solenoid.
9
ATC Disabled to Prevent
Brake Fade
ATC is temporarily disabled to prevent excessive heating of the foundation brakes.
10
Tire Size Out of Range
(Front to Rear)
Verify correct tire size as desired. Verify proper tire inflation. Verify correct number of
exciter ring teeth. Verify that the ECU has the proper tire size settings.
11
Wheel Speed Sensors
Reversed on an Axle
Sensors are reversed (left to right) on one of the axles. Verify proper installation,
connection, and wiring of the sensors.
