1428-1429 / 1904
ENGINE
DTC
DESCRIPTION
CAUSE
DIAGNOSTIC
LAMP (
MIL
)
DIAGNOSTIC
LAMP (
CEL
)
Gil When
Driven In CNG
PROBABLE TROUBLE AREA
P0136
Downstream
Oxygen Sensor
signal error/short
Circuit
Open circuit/Short
Circuit to Ground
ON
OFF
ON
1) Loose/ Damaged Connections or Intermittent fault.
2) Sensor supply line Short circuit to Battery/ Ground.
3) Sensor Signal line Short circuit to Battery/ Ground.
4) Check the continuity from sensor connector pins to the ECU pins.( ECU pin 155- Sensor Pin 1; ECU pin 239- Sensor Pin 2; ECU Pin
206-Sensor Pin 3; ECU pin 202- Sensor pin 4.).
5) Check for back out of pins at both Sensor connector and ECU connector.
6) Check for damage of pins at both sensor connector and ECU connector.
7) Faulty Downstream HO2S2 Sensor.
8) Faulty ECU
P0138
Downstream
Oxygen Sensor
Circuit short to
battery
Short Circuit to
Battery
ON
OFF
ON
P0139
Downstream
Oxygen sensor
slow response
Slow response of
the sensor voltage
ON
OFF
ON
P0140
Downstream
Oxygen Sensor
Circuit Signal non
plausible
Signal Out of range
ON
OFF
ON
P0141
Downstream
Oxygen Sensor
Heater Control
Circuit Open
/Short Circuit
Open/Short Circuit
ON
ON
OFF
ON
P0171
Less fuel quantity
than required –
gasoline mode
------
ON
OFF
ON
1. Blocked fuel line
2.Bad fuel regulator
3. Blocked/leaking injectors
4.Injector delay time not correct
5.Air leakage through intake
P0172
Higher fuel
quantity than
required –
Gasoline mode
------
ON
OFF
ON