Komatsu SAA6D114E-3 - Code [2556;CA2556] Intake Air Heater Relay Supply Voltage High Error

SEN00460-01 40 Troubleshooting
54 114E-3 Series
E-56 Code [2556/CA2556] Intake Air Heater Relay Supply Voltage High
Error 1
Error code Failure code
Trouble Short circuit in intake air heater relay
2556 CA2556
Contents of
trouble
• There is short circuit in intake air heater relay.
Action of
controller
• None in particular.
Problem that
appears
on machine
• Intake air heater does not function.
(Poor starting performance, white exhaust smoke at low temperature)
Related infor-
mation
• Method of reproducing failure code: Starting switch ON when coolant temperature is –4°C or less.
Possible
causes and
standard value
in normal state
Causes Standard value in normal state/Remarks on troubleshooting
1
Defective auto preheat relay
(Internal disconnection)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON. (Test relay unit).
R18 (male) Resistance
Between (1) – (2) 300 – 600 z
a Prepare with starting switch OFF, then turn starting switch ON
and carry out troubleshooting. (Test by replacing relay unit.)
Replace auto preheat relay (R18) with other relay. If mark E of fail-
ure code disappears after reproduction operation is conducted, that
relay has a defect.
2
Ground fault in wiring har-
ness (Short circuit with GND
circuit)
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between J2 (female) (40) –
R18 (female) (1)
Resis-
tance
Min.
100 kz
3
Short circuit in wiring har-
ness (With another wiring
harness)
a Troubleshoot with starting switch OFF, then carry out trouble-
shooting without turning starting switch ON.
Wiring harness among all pins between J2
(female) (40) – J2 (female) (With also R18
disconnected)
Resis-
tance
Min.
100 kz
4
Defective wiring harness
connector
Connecting parts among auto preheat relay, engine unit wiring har-
ness, and engine controller are suspected. Inspect them directly.
• Loose connector, broken lock, broken seal
• Corrosive, bent, broken, forced-in, or extended pin
• Humidity in connector, entry of dirt or dust, poor insulation
5 Defective engine controller
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
J2 (female) Resistance
Between (40) – (42) 300 – 600 z