Case IH AFX8010 Repair Manual page 1143

Start control Start switch - Short circuit to B+ (B.80.A.90.82 -
G.30.B.54)
AFX8010
E0168-03 - CCM2 Key Switch Voltage
Context:
Key switch voltage is used to initialize (wake-up) the module, and also supplies power to the 5V and 8V regulators
for the regulated voltage circuits. The module will shutdown if the voltage is less than 9 volts, but there is no
shutdown for excessive voltage.
Cause:
The CCM2 key switch power supply circuit is shorted to a higher than normal source.
Possible failure modes:
1.
Circuit wiring shorted to high voltage source.
2.
Faulty alternator/regulator.
3.
Controller internal failure (internal regulator failure).
Solution:
1. Start the combine engine . Enter the Universal Display Plus "DIAG" screen. Select the "VOLTAGE" sort menu,
and select "CCM2 KEY SW" to check the voltage range.
Increase the engine RPM to high idle (maximum) and check voltage range.
The acceptable voltage range for the module is 10 - 18 volts.
A. If the voltage reading is greater than 18 volts, continue with Step 2.
B.
If the voltage reading is between 10 - 18 volts, continue with step 5.
2. Shut off the combine engine . Enter the Universal Display Plus "DIAG" screen. Select the "VOLTAGE" sort
menu, and select "CCM2 KEY SW" to check the voltage range.
The acceptable voltage range for the module is 10 - 18 volts.
A. If the voltage reading is between 10 - 18 volts, the alternator and/or regulator has failed, and is
producing excessive voltage. Refer to Alternator - Problem solving (A.30.A.82 - G.40.A.30) for
additional alternator testing information.
B. If the voltage reading is greater than 18 volts, continue with step 3.
3. Turn off the key switch to power down the system. Use a multimeter to check the voltage at fuse F-38.
A. If the voltage reading is greater than 18 volts, then there is a fault in the wiring of the 24V starting system.
Refer to STARTING SYSTEM - Problem solving (B.80.A - G.40.A.30) for additional information.
B. If the voltage reading is between 10 - 18 volts, continue with step 4.
4. Remove the instructional seat and storage bin to gain access to the CCM2 connector X015. Turn the key
switch ON. Use a multimeter to check the voltage at connector X015 pin J1-4.
A. If the voltage reading is greater than 18 volts, then a high voltage source has been connected to one of
the following wires in the cab main (CM) harness:
- wire 053 red, fuse F38 to key switch S-02 pin 1
- wire 125 red, fuse F38 to ECU Power relay K14 pin 1
- wire 859 orange, key switch S-02 pin 5 to ECU connector X193 pin 15
- wire 096 orange, key switch S-02 pin 6 to CM harness splice
- wire 055 orange, CM harness splice to Road Light switch S-26 pin 6
- wire 095 orange, CM harness splice to CCM1 Power relay K24 pin 1
POWER PRODUCTION - STARTING SYSTEM
9677 1 27/05/2004
B.80.A / 41