Discussion:
Check engine light on

Note: I did enter the wrong model #, It is actually a GC25P5. I have a tier lll Doosan with 3 faults listed: 721, 772, and 921. It starts and runs, ( a little rough, and after reaching operating temp. it runs rich) My motoservice will connect and read the motor, but I have no chart for 3 digit codes. Any help is appreciated. Thanks.
  • Posted 18 Jan 2013 03:46
  • Modified 18 Jan 2013 04:42 by poster
  • By roadtek
  • joined 4 Dec'07 - 123 messages
  • Massachusetts, United States
Showing items 1 - 1 of 1 results.
Code 712:

GasFuelAdaptRangeLo
In LPG mode, system had to
adapt rich more than expected

Check: Check for vacuum leaks.
Check fuel trim valves, e.g. leaking
valve or hose
Check for missing orifice(s).

Code 772:

GasPostO2FailedRich
Pre-catalyst O2 sensor indicates
extended rich operation on LPG

Check: Correct other faults that may
contribute to 772 (e.g. faults
pertaining to FTVs, Pre-Cat O2,
Post Cat O2 sensor)
Look for leaks in exhaust, catalytic
converter, HEGO sensors; repair
leaks.
Check all sensor connections (see
fault 742 corrective actions).

Code 921:

O2RangeHigh
Pre-catalyst O2 sensor voltage
out of range high, sensor signal
shorted to power

Check: Check if O2 sensor installed before
catalyst is shorted to +5Vdc or
battery.
O2 (signal) Pin 3 to SECM Pin B13
SECM (XDRP + 5V) Pin B24
SECM (DRVP + 12V) Pin A23
  • Posted 18 Jan 2013 07:13
  • By kevin_t
  • joined 2 Dec'10 - 1,301 messages
  • Pennsylvania, United States

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