CHECK ENGINE LIGHT - Fuel Trim Malf.

[thexyz]

I bought a 98 GSX from a car dealership. Two days later I was driving along and the check engine light came on. I checked it at work and it said "PO 170 Fuel Trim Malfunction" (I think the code was PO170... But that doesnt matter.)

And my sister has a 98 GS-T and a full tank gets about 270 miles, and I noticed my first whole tank of gas only got about 140. So I knew something wasnt right..

Anyways I brought it to Tuffy's Auto Centre next door to my work after I erased the check engine light and the guy said nothing was wrong.

But what the hells up?

Some internet sites said possible CO2 Sensor.

I just hope its not something expensive. I love this car so much.


---- ALSO ALSO ALSO ALSO ALSO ALSO ----

The third brake light that hangs by the hatch rattles, can i stop it? Thanks.

[thexyz]

Also, one of my halo lights for the projectors (the running light halo) is out. How can I get another.

[david-b]

For the light I don't know if the bulbs on those come out. If it does, you should be able to replace it. I've heard that a lot don't come out though, so you may have to buy a new headlight.

Brake light... Check all screws. If still rattles, add something like rubber underneath it so it's not rattling on the car or glass or whatever

Dont know that CEL, so cant help you there.

[AbsoluteGTR]

For the CEL. It might be your upstream 02 sensor. Try resetting you ECU first, so it will reset your air/fuel maps and everything. To do this just disconnect the battery for about 20 minutes,

I agree with david on the third brake light issue.

As for you Halo, once those badboys burn out they are gone for good. *For next time though* If you put a fuse in the circuit though (between halo and parking light) it is supposedly supposed to not blow out!

GL

[david-b]

Originally Posted by AbsoluteGTR

As for you Halo, once those badboys burn out they are gone for good. *For next time though* If you put a fuse in the circuit though (between halo and parking light) it is supposedly supposed to not blow out!

If the bulb actually burns out though, that's not going to save it. The fuse will stop if there is a surge or power gets too much, but won't save the bulb itself from burning out. Eventually, all lights burn out.

[AbsoluteGTR]

I see what you are saying. But I just read that the halos require less voltage then the parking lights do. SO, if you put a fuse in the middle of the two, it will protect the light. I have had these halos before on my previous 2g and I doubt a light should burn out in a week, as mine did, but I just hooked it straight up to the park light...

*EDIT>> Just found the following in a thread in the interior subforum*

Originally Posted by Black99GST

yeah. i dont remember the amprage (s/p) of the Halo, but i belive its probably 10 amps or so... but if you place a fuse between the parking light, and the positive wire on the halo, that will keep it from burning out. my buddy went through a set of halo projectors in a week, then asked me for advice when he bough new ones... we stuck a fuse in the mix, and the halo's have been working evey day for about 11 months now

[david-b]

Eh, you learn something new everyday. Going to remember that for when I get mine next year.

[gthompson97]

If you're really good with wiring and what not, they're a writeup on dsmtuners.com about replacing the halo lights. Seems like quite a bit of work, but you can customize them with your own colors and what not. I may try it when I get some new headlights.

About your CEL,

DTC P0170: FUEL TRIM MALFUNCTION
DTC Set Criteria
Engine is in closed loop control. Engine coolant temperature is more than 14°F (-10°C). Intake air temperature is 14°F (-10°C) or more. Barometric pressure is 11 psi (76 kPa) or more. Volume Airflow (VAF) sensor output frequency is 113 Hz or more. Code will set if long-range fuel correction is -12.5 percent or less, or 12.5 percent or more, for 10 seconds. Code will also set if short-range fuel correction is -10 percent or less, or 10 percent or more, for 10 seconds.

Probable Cause
VAF failed.
Injector failed.
Incorrect fuel pressure.
Air intake system leak.
Heated Oxygen Sensor (HO2S) failed.
Engine Coolant Temperature (ECT) sensor failed.
Intake Air Temperature (IAT) sensor failed.
Barometric Pressure (BARO) sensor failed.
Exhaust system leak.
Incorrect fuel used.
Engine Control Module/Powertrain Control Module (ECM/PCM) failed.

Diagnostic Procedure
1. Read scan tool data list item No. 13 (intake air temperature). If temperature displayed on scan tool is equal to actual air temperature as measured with a thermometer, go to next step. If temperature displayed on scan tool is not equal to actual air temperature, check air temperature circuit. See DTC P0110: INTAKE AIR TEMPERATURE (IAT) CIRCUIT MALFUNCTION .

2. Read scan tool data list item No. 21 (engine coolant temperature). If temperature displayed on scan tool is equal to actual engine coolant temperature as measured with a thermometer, go to next step. If temperature displayed on scan tool is not equal to actual coolant temperature, check engine coolant temperature circuit. See DTC P0115: ENGINE COOLANT TEMPERATURE (ECT) CIRCUIT MALFUNCTION .


3. NOTE: Scan tool data list item No. 25 may not be available on generic scan tool. This function is available on MUT-II scan tool.

Read scan tool data list item No. 25 (barometric pressure). Compare readings with BAROMETRIC PRESSURE table. If scan tool reading is as specified, go to next step. If scan tool reading is not as specified, check barometric pressure circuit. See DTC P0105: BAROMETRIC PRESSURE CIRCUIT MALFUNCTION .

BAROMETRIC PRESSURE
Altitude /\ Ft. (m) /\ kPa
0 /\ (0) /\ 101
1969 /\ (600) /\ 95
3937 /\ (1200) /\ 88
5906 /\ (1800) /\ 81


4. Disconnect fuel injector connector. Check resistance across fuel injector terminals. Resistance at 68°F (20°C) should be 2-3 ohms on 2.0L turbo engine, or 13-16 ohms on 2.4L engine. If resistance is as specified, go to next step. If resistance is not as specified, replace fuel injector, and go to step 16 .

5. Using stethoscope, check injector operating sound during cranking and at idle. Ensure frequency of operating sound increases as engine RPM increases. If injectors are okay, go to next step. If no operating sound is heard from an injector, check wiring harness between injectors and ECM/PCM. Also, check fuel injector connectors and ECM/PCM connectors. Repair as necessary, and go to step 16 . If wiring and connectors are okay, replace ECM/PCM, and go to step 16 .

6. Perform fuel pressure test. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If fuel pressure is okay, go to next step. If fuel pressure is not within specification, repair as necessary, and go to step 16 .

7. Read scan tool data list item No. 81 (long-term fuel trim). On Eclipse, if fuel trim is less than zero (during closed loop), go to next step, or if fuel trim is more than zero (during closed loop), go to step 9 . On Montero Sport or Galant, if fuel trim is less than zero (during closed loop), go to step 14 , or if fuel trim is more than zero (during closed loop), go to step 11 .

8. Read scan tool data list item No. 12 (volume airflow). Reading should be from 18-44 Hz at idle to 63-103 Hz at 2500 RPM on 2.4L, or 22-48 Hz at idle to 60-100 Hz at 2500 RPM on turbo engine. Ensure frequency increases as RPM is increased. If scan tool reading is more than specification or does not increase with RPM increase, replace VAF sensor, and go to step 16 . If scan tool reading is less than or equal to specification, check for leaking injectors and fuel contamination. Repair as necessary. If injectors and fuel are okay, replace ECM, and go to step 16 .

9. Check air intake system for leaks or obstructions. If air intake system is okay, read scan tool data list item No. 12 (volume airflow). Reading should be from 18-44 Hz at idle to 63-103 Hz at 2500 RPM on 2.4L, or 22-48 Hz at idle to 60-100 Hz at 2500 RPM on turbo engine. Ensure frequency increases as RPM is increased. If scan tool reading is less than specification or does not increase with RPM increase, replace VAF sensor, and go to step 16 . If scan tool reading is more than or equal to specification, go to next step.

10. Check for exhaust leaks at HO2S fittings, exhaust manifold, or front pipes. Check for fuel filter and/or fuel line blockage. Check for blocked injectors. Check fuel pump for poor fuel supply. Check fuel for contamination. Repair as necessary. If no problems are found, replace ECM, and go to step 16 .

11. Check air intake system for leaks, dirt, blockage and correct assembly. Repair as necessary. Than go to step 16 . If air intake system is okay, go to next step.

12. Read scan tool data list item No. 12 (volume airflow). Reading should be from 25-51 Hz at idle to 80-120 Hz at 2500 RPM. If reading is within specification, go to next step. If reading is not within specification, replace VAF sensor, and go to step 16 .

13. Check for fuel filter and/or fuel line blockage. Check for blocked injectors. Check fuel pump for poor fuel supply. Check fuel for contamination. Check for exhaust leaks. Repair as necessary, and go to step 16 . If no problems are found, replace ECM/PCM, and go to step 16 .

14. Read scan tool data list item No. 12 (volume airflow). Reading should be from 25-51 Hz at idle to 80-120 Hz at 2500 RPM. If reading is within specification, go to next step. If reading is not within specification, replace VAF sensor, and go to step 16 .

15. Check for blocked injectors. Check fuel for contamination. Repair as necessary, and go to next step. If injectors and fuel are okay, replace ECM/PCM, and go to next step.

16. Test drive vehicle following OBD-II drive cycle pattern. See FUEL TRIM MONITOR under OBD-II DRIVE CYCLES in SELF-DIAGNOSTICS - INTRODUCTION article. Check readiness test status. If readiness test status is complete, repair is done. If readiness test status is incomplete, drive vehicle in OBD-II Fuel Trim monitor pattern again. Check scan tool for DTCs. Confirm DTC does not reset.

[eclipsed at 3am]

gthompson that was amazing

[l_eclipse_l]

Originally Posted by eclipsed at 3am

gthompson that was amazing

Simple copy and paste man, he just had to find the info.

[eclipsed at 3am]

well i mean, its a great find, you know? i wouldnt know where to find that. everyone on here is being grouchy today.

[gthompson97]

It's a secret

Haha, no I have Mitchell On-Demand on my computer so I can get pretty much anything for any car. But it won't let me do the copy paste thing. I have to drag it over and then it gets all jumbled and shit so I gotta take 5 mins and fix it up so it's understandable. Still simple though.