Operation Section
79
Table 2. Diagnostic Fault Codes (Flash Codes) cont’d.
DFC
PROBABLE FAULT
FAULT ACTION *
CORRECTIVE ACTION FIRST CHECK
852
LiqPostO2FailedLean
Pre-catalyst O2 sensor indicates
extended lean operation on
gasoline
(1) TurnOnMil
(2) DisableLiqPost
O2Ctrl
Correct other faults that may contribute to
852 (e.g. faults pertaining to Injectors, MAP,
IAT, Pre-Cat O2, Post Cat O2 sensor)
Look for leaks in exhaust, catalytic converter,
HEGO sensors; repair leaks.
Check all sensor connections (see fault 842
corrective actions).
871
LiqO2FailedRich
Pre-catalyst O2 sensor indicates
extended rich operation on
gasoline
(1) TurnOnMil
(2) DisableLiquid O2Ctrl
High gasoline fuel pressure, perform gasoline
pressure test
Injector problems, e.g. leaking, defective
injector
872
LiqPostO2FailedRich
Pre-catalyst O2 sensor indicates
extended rich operation on
gasoline
(1) TurnOnMil
(2) DisableLiq
PostO2Ctrl
Correct other faults that may contribute to
872 (e.g. faults pertaining to Injectors, MAP,
IAT, Pre-Cat O2, Post Cat O2 sensor)
Look for leaks in exhaust, catalytic converter,
HEGO sensors; repair leaks.
Check all sensor connections (see fault 842
corrective actions).
911
O2RangeLow
Pre-catalyst O2 sensor voltage
out of range low, sensor signal
shorted to ground
(1) TurnOnMil
(2) DisableLiquid O2Ctrl
(3) DisableGas O2Ctrl
Check if O2 sensor installed before the
catalyst is shorted to GND or sensor GND.
O2 (signal) Pin 3 to SECM Pin B13
SECM (DRVG GND) Pins A16, B17
SECM (XDRG sensor GND) Pin B1
912
O2_PostCatRangeLow
Post-catalyst O2 sensor voltage
out of range low, sensor signal
shorted to ground
(1) TurnOnMil
(2) Disable asoline
Post-catalyst O2Ctrl
(3) Disable LPG
Post-catalyst O2Ctrl
Check if O2 installed after the catalyst sensor
is shorted to GND or sensor GND.
O2 (signal) Pin 3 to SECM Pin B19
Possible sources: SECM (DRVG GND) Pins
A16, B17 and SECM (XDRG sensor GND)
Pin B1
921
O2RangeHigh
Pre-catalyst O2 sensor voltage
out of range high, sensor signal
shorted to power
(1) TurnOnMil
(2) DisableLiquid O2Ctrl
(3) DisableGas O2Ctrl
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
922
O2_PostCatRangeHigh
Post-catalyst O2 sensor voltage
out of range low, sensor signal
shorted to ground
(1) TurnOnMil
(2) Disable asoline
Post-catalyst O2Ctrl
(3) Disable LPG
Post-catalyst O2Ctrl
Check if O2 sensor installed after catalyst is
shorted to +5Vdc or battery.
O2 (signal) Pin 3 to SECM Pin B19 Possible
voltage sources: SECM (XDRP + 5V) Pin
B24 and SECM (DRVP + 12V) Pin A23
931
FuelTempRangeLow
Fuel Temperature Sensor Input
is Low normally set if the fuel
temperature sensor wire has
shorted to chassis ground or the
sensor has failed.
TurnOnMil
Check fuel temp sensor connector and wiring
for a short to GND
SECM (signal) Pin B14 to FTS Pin 1
SECM (sensor GND) Pin B1 to FTS Pin 2
SECM (system GND) Pin A16, B17
932
FuelTempRangeHigh
Fuel Temperature Sensor Input
is High normally set if the fuel
temperature sensor wire has
been disconnected or the circuit
has opened to the SECM.
TurnOnMil
Check if fuel temp sensor connector is
disconnected or for an open FTS circuit
SECM (signal) Pin B14 to FTS Pin 1
SECM (sensor GND) Pin B1 to FTS Pin 2
(*) Fault actions shown are default values specified by the OEM.