Troubleshooting
Error
Code
Error
Location
Type Name Cause Solution
Wiring problem. Check wiring between
HPTCM and contactor.
Look for shorted wire
between HPTCM and
contactor terminals A1
and A2.
A4CH Hose ALARM High Relay
Current Hose
Shorted contactor. Measure resistance
between A1 and A2
terminals. The resistance
should be about 289Ω.
If contactor is measuring
less than 100Ω, then the
contactor is shorted and
should be replaced.
A4CM MCM ALARM High MCM
Current
MCM is drawing too
much current from the
system.
If problem continues
replace MCM. See system
repair manual.
Short circuit in booster
heater wiring.
Check wiring for touching
wires.
A4DA
A4DB
Boost A
Boost B
ALARM High Heater
Current
Bad heater. Measure resistance of
heater(s), replace if
needed. See system
repair manual.
Check continuity of
transformer windings,
normal reading are about
0.2Ω onbothprimaryand
secondary. If reading is
0Ω replace transformer.
A4DH Hose ALARM High Heater
Current
Short circuit in hose
wiring.
Check for shorts between
the primary winding and
the support frame of the
transformer.
3A1705J 75