Doosan G20P-5, Service Manual, Page: 257 / 306

G424F(FE) Service Manual Chapter 9. Advanced Diagnostics 255
Table 1. Fault List Definitions (cont’d.)
FAULT DESCRIPTION
CODE
(MI04 CODE)
GasFuelAdaptRangeHi In LPG mode, system had to adapt lean more than expected
731
(73)
GasFuelAdaptRangeLo In LPG mode, system had to adapt rich more than expected
721
(72)
GasO2FailedLean
Pre-catalyst O2 sensor indicates extended lean operation on
LPG
751
GasO2FailedRich
Pre-catalyst O2 sensor indicates extended rich operation on
LPG 771
(77)
GasO2NotActive
Pre-catalyst O2 sensor inactive on LPG, open O2 sensor
signal or heater leads, defective O2 sensor, or defective FTVs 741
(74)
GasPostO2FailedRich
Post-catalyst O2 sensor control on LPG has reached rich limit
and sensor still reads to lean. This could be caused by oxygen
leak before or just after sensor, catalyst failure, sensor failure,
or wiring/relay failure causing the sensor to not be properly
heated. If any Pre-O2 sensor faults are set, diagnose these
first and after correcting these faults recheck if this fault sets.
772
GasPostO2FailedLean
Post-catalyst O2 sensor control on LPG has reached lean limit
and sensor still reads to rich. This could be caused by catalyst
failure, sensor failure, or wiring/relay failure causing the
sensor to not be properly heated. If any Pre-O2 sensor faults
are set diagnose, these first and after correcting these faults
recheck if this fault sets.
752
GasPostO2Inactive
Post-catalyst O2 sensor control on LPG has sensed the O2
sensor is not responding as expected. If any Pre-O2 sensor
faults are set diagnose these first and after correcting these
faults recheck if this fault sets. Possible causes for this fault
are sensor disconnected, sensor heater failed, sensor
element failed, heater relay, or SECM control of heater relay
is disconnected or failed.
742
Reserved for Future Use 743