fault code

[patrick cooper]

after the ,check engine light, came on it was pluged up to diostonic computer but the garage is not a isuzu dealer and had never seen a vcross before the code shows p1393 the vx is a japaneese inport 1997 right hand drive ,the engineer in garage suspected it is the mass flow sensor on the air intake or the oxygen sensor, the engine is v6 3.2 ive tryed scrapyards to get one but none about .do these go faulty is their something i can check air filter is good no drop in power ,or will i have to order a new one to plug it on to find it was the oxygen sensor after all any ideas???

[Joe_Black]

The P1393 error on the VX indicates a voltage condition from the G-Sensor which determines whether or not you're bouncing around off-road so it can tell if what the VSS and crank-angle sensors are telling the ECU is true.

The G-sensor is located in the center console directly underneath the armrest storage area and behind the e-brake pivot. Remove your center console (real easy if you take the seats out which is also easy) and trace the wiring from the G-sensor forward to make sure the connectors are properly seated and that there's no damage to the wiring. If you've got electronic skills and test equipment you may be able to diagnose the component yourself. Here's a basic description of the G-sensor:


Circuit Description
The Gravity (G) sensor is a vertical low-g (gravity) acceleration sensor. By sensing vertical acceleration caused by bumps or potholes in the road, the powertrain control module (PCM) can determine if the changes in crank- shaft speed are due to engine misfire or are driveline induced. If the G sensor detects a rough road condition, the PCM misfire detection diagnostic will be de-activated. The G sensor at rest output should be between 2.35 - 2.65 volts (+1G). During a rough road condition, the voltage output can vary between 0.5 volt (-1G) and 4.5 volts (+3G).

Conditions for Setting the DTC

Engine running.
No vehicle speed.
G sensor signal indicates greater than 2.5 volts (+1G) or less than 1.5 volts (0G) for one minute.

The G-sensor is present in many Isuzu 4X4 vehicles so you should be able to locate one either new or from a breaker.

[patrick cooper]

wiped out seat and found g sensor voltage between outside wires 3 in total was 2.49 v when i unbolted g sensor from floor and tilted it to app 35 degries eg going up hill the voltage changed to 1.01v looks as if its working wot now ?

[Joe_Black]

As a vertical g-sensor it shouldn't react to being tilted. And if it was reading 2.49 while level and still then then you likely have a bad sensor. Double check your reading with the sensor fastened in place and not being disturbed.

If you go looking for a replacement keep in mind that it should be the same part from a Trooper or Rodeo in the same year range.

[patrick cooper]

bolted it back in g sensor,started engine reading 2.49v to the outside wires .brown wire to center wire reads 4.94v unbolted it again and shook it up and down gently voltage all over the place 1.7v-2.55v moved sensor to 45degrees down hill 3.8 volts and on a 30degree side hill dident move voltage much 1020pm at night will check scrapyards tomorow thanks