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Subaru P0103 code

Tiny
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The problem came back after 80 miles, I heard it could be a air filter problem that has oil or something in it. The air filter is very clean but I am running out of ideas. Does this sound plausible?
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Friday, January 21st, 2011 AT 10:15 PM
Tiny
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Ok, the filter they are talking about is the K & N Filters, they are reusable filters, you clean them every so often with a K & N Cleaner and there is an Oil that you spray on the filter. These filters have been known to cause problems with some MAF Sensors because of the Oil.

If you happen to be using a K&N Filter try putting a standard air filter in it.

Ok, I need to do some check. But I was just reading through some more of the info I have and possible causes. And there is mention of 2 relays for the MAF - One provides power and one for the burn-off cleaning cycle. This is on Bosch MAF's.
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Saturday, January 22nd, 2011 AT 2:20 AM
Tiny
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Ok, so sorry for the late response but have been busy with school. The problem has been off and on. While trying to get a new air filter the car stalled out and wouldn't start. I thought it was done but then a minute or so later I tried to start it and it started and got me to the auto parts store. I got to the store cleaned the mass air flow sensor, changed the filter, and then reconnected the negative wire. I think it was just the fact that the battery was disconnected but the check engine light went off. I made it back home with no problems and then parked it. I came back out a hour later and then let it run at idle for 5-10 minutes or so and everything seemed fine. I was starting to celebrate that the problem was fixed and the check engine light remained off and then all of a sudden and quietly the engine shut off. The CEL came back on and the same symptoms came back on. I disconnected the negative cable till the check engine light went off again and let it run for a while and then the same thing happened and every time i started it after that the same seemingly MAF symptoms occurred.

So tomorrow I am going to try and drive it 7 miles to the closest place I can get someone to pull the code. It is a bosch MAF, I'm pretty sure, and here is a link to one that looks like the one I got, http://www.autopartswarehouse.com/sku/Subaru/Impreza/Bosch/Mass_Air_Flow_Sensor/1998/L/4_Cyl_2-dot-2L/W0133-1598555.html?tlc=Engine+%26+Drivetrain&intcmpid=

So I have been thinking it may be a bad ground but it looks fine. I thought maybe it could be the iacv again because it only stalls out when the engine heats up and the rpms lower. But I don't know if that makes sense for why after I start it again it shows mass air flow sensor problems happen. I was also wondering if the TPS could have anything to do with it, I had it go to a mechanic a while back for something else and he said the TPS needed to be tuned. The car does stay on if I keep my foot on the accelerator while idling.

Does the 2 relay idea still seem valid and I should try and change the wires and put a new harness on? I am going to a autozone so if the code comes up mass air flow sensor I'll get a new one with the warranty but I don't know if it is worth it if there is a different problem causing it.

I talked to a guy at autozone last month and he said I would be surprised how many of the refurb MAF sensors come back. I don't know if that is the problem and I need to try and find a new one or something but any ideas would be appreciated.
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Friday, February 25th, 2011 AT 4:50 PM
Tiny
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Ok, cannot find a test for checking the TPS with a Volt Meter. The only test is with a scan tool that can read Throttle Angle and Voltage. If you can find one to use the voltage should be between 0.45 - 0.55 at O degree Throttle Angle with key in on position not running. If out of spec then just loosen screws and adjust to spec.

Also, the computer could still be bad, I have come across a few that were bad and it only affecting one sensor.
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Monday, February 28th, 2011 AT 3:29 AM
Tiny
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So I don't think the tps would be shorting out my MAF right? I can live with it untuned, but the about computer is there a test I could do to see if it is bad, a ecu isn't cheap so it would not be worth me just replacing and seeing if it is bad? Also would a bad ecu cause this kind of problem? I went to auto zone and I got a P0102 code this time, low input MAF as opposed to high input. Also searching online would a wire harness be more likely in this situation? Or is the fact two different codes more symptomatic of the computer? I have a new maf in and the problem has disappeared but I have a feeling it will be back
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Tuesday, March 1st, 2011 AT 3:24 AM
Tiny
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Testing

DTC P0102 (QA_LOW): MASS AIRFLOW (MAF) SENSOR CIRCUIT LOW INPUT

1. Turn ignition off. Connect scan tool. Start engine. Observe display for mass airflow and voltage signal values from MAF sensor. If values are between 1.3 g/sec and 250 g/sec or.3-5.0 volts, system has returned to normal. Check circuit between PCM and MAF sensor for intermittent opens or shorts, or PCM and MAF sensor connectors for poor contact. If airflow is not within specifications, go to next step.

2. Start and idle engine. Using voltmeter connected to ground, measure voltage (backprobe) at PCM connector terminal No. 5 (Pink/Blue wire on Forester and Impreza, or White wire on Legacy). If voltage reading is less than.3 volts, go to next step. If voltage reading is more than.3 volts, wiggle PCM connector. If voltage reading changes to less than.3 volts, check PCM connector for poor contact.

3. Turn ignition off. Disconnect MAF sensor. Turn ignition on. Measure voltage at MAF connector terminal No. 1 (Yellow/Green wire on Forester and Impreza, or Yellow/Blue wire on Legacy). If voltage reading is more than 10 volts, go to next step. If voltage reading is 10 volts or less, repair open circuit between main relay and MAF sensor.

4. Turn ignition off. Disconnect PCM. Check resistance of harness between PCM connector terminal No. 5 and MAF connector terminal No. 4 (Pink/Blue wire on Forester and Impreza, or White wire on Legacy). If resistance is one ohm or less, go to next step. If resistance is more than one ohm, repair wiring or poor connection.

5. Measure resistance of harness between PCM connector terminal No. 53 and MAF connector terminal No. 3 (Black/Green wire on Forester and Impreza, or Pink wire on Legacy). If resistance is one ohm or less, go to next step. If resistance is more than one ohm, check for open in harness between PCM and MAF sensor or for poor contact at PCM or MAF sensor connectors.

6. Check resistance of harness between ground and PCM connector terminal No. 5 (Pink/Blue wire on Forester and Impreza, or White wire on Legacy). If resistance is more than one megohm, replace MAF sensor. If resistance is one megohm or less, repair short in ground circuit between PCM and MAF sensor.

DTC P0103 (QA_HI): MASS AIRFLOW (MAF) SENSOR CIRCUIT HIGH INPUT

1. Turn ignition off. Connect scan tool. Start engine. Observe display for mass airflow and voltage signal values from MAF sensor. If values are between 1.3 g/sec and 250 g/sec or.3-5.0 volts, system is normal. Check for poor connections or intermittent open circuits. If values are not within specifications, go to next step.

2. Turn ignition and scan tool off. Disconnect MAF sensor. Turn ignition and scan tool on. Observe display for mass airflow and voltage signal from MAF sensor. If values are less than 250 g/sec or 5.0 volts, replace MAF sensor. If values are greater than 250 g/sec or 5.0 volts, check for short to power in harness between MAF sensor and PCM. After repairing short, check PCM operation and replace if necessary. Retest system.
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Thursday, March 3rd, 2011 AT 6:58 PM

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