Code [2556/Ca2556] Intake Air Heater Relay Supply Voltage High Error - Komatsu 114E-3 Series Shop Manual

SEN00460-01
E-56 Code [2556/CA2556] Intake Air Heater Relay Supply Voltage High
Error
Error code Failure code
2556 CA2556
Contents of
• There is short circuit in intake air heater relay.
trouble
Action of
• None in particular.
controller
Problem that
• Intake air heater does not function.
appears
(Poor starting performance, white exhaust smoke at low temperature)
on machine
Related infor-
• Method of reproducing failure code: Starting switch ON when coolant temperature is –4°C or less.
mation
Defective auto preheat relay
1
(Internal disconnection)
Ground fault in wiring har-
2 ness (Short circuit with GND
Possible
circuit)
causes and
standard value
in normal state
Short circuit in wiring har-
3 ness (With another wiring
harness)
Defective wiring harness
4
connector
5 Defective engine controller
54
Trouble Short circuit in intake air heater relay
Causes
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON. (Test relay unit).
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.
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Wiring harness between J2 (female) (40) –
R18 (female) (1)
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)
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
a Prepare with starting switch OFF, then carry out troubleshooting
without turning starting switch ON.
Standard value in normal state/Remarks on troubleshooting
R18 (male)
Between (1) – (2)
J2 (female)
Between (40) – (42)
40 Troubleshooting
1
Resistance
300 – 600 z
Resis- Min.
tance 100 kz
Resis- Min.
tance 100 kz
Resistance
300 – 600 z
114E-3 Series