New Holland CX720 Repair Manual page 2314

E0139-04-Key Switch - Start Shorted to Low Source (B.80.A.90.82 -
G.30.B.53)
E0139-04 - Key Switch - Start Shorted to Low Source
Cause:
The key switch (S02) circuit is shorted to ground.
Possible failure modes:
1. Switch supply wiring shorted to ground.
2. Controller internal failure (internal regulator failure).
Solution:
1. Enter the InfoView monitor - "Diagnose info" screen.
Select "CCM2" sub menu.
Select " key switch - start" and check voltage range. Operate the switch.
The normal operating range for the key switch circuit is 10.0 - 18.0 volts.
A. If the voltage reading is low (0 - 0.5 volts) out of range continue with Step 2.
B. If the voltage reading is within the proper limits. Continue the troubleshooting at step 5.
NOTE: Visually inspect the wiring harness and connectors. Verify that the connector was fully installed. Inspect
the terminals and wires at the connector for pushed back or corroded terminals or damaged wires. Flex the
harnesses involved to reveal intermittent breaks or shorts in the wiring concerned.
2. Disconnect the key switch connector X068. Install a jumper wire between pins 1 and 6.
A. If the voltage increases into the proper range, the short is in the switch. Replace the switch.
B. If the voltage remains low on InfoView monitor continue with Step 3.
3. Check for voltage at Fuse F-38.
A. If voltage found is in the normal range, the short is on wire 053 red. Find and repair the short.
B. If the voltage found is low, check the charging system and repair as necessary.
4. Disconnect connector X015 pin J1-4 and measure voltage at the disconnected pin.
A. If the voltage found is low the short is on wire 096 orange. Find and repair the short.
B. If the voltage found is in the normal range there is an internal regulator failure. Replace the CCM2 con-
troller.
5. Operate the machine while monitoring InfoView monitor. If no low out of range readings are indicated, erase
the fault code and continue operation.
A.
Series 1206-1347
Wiring harness - Electrical schematic frame 24 (A.30.A.88-C.20.E.24)
Series 1348 and above
Wiring harness - Electrical schematic frame 29 (A.30.A.88-C.20.E.29)
POWER PRODUCTION - STARTING SYSTEM
2 4/7/2006
B.80.A / 6