jemcdon

Hi, I have a 2001 subaru outback, 2.5L, manual base model with 101K miles on it. The car has been throwing a P0122 code persistently for a while now. At first, the code was rarely thrown (about a year ago) and only just after starting up the car. I have not had an occassion where the code was thrown outside of the initial cold start. The code will be thrown within the first minute of the car starting. This code corresponds to the TPS circuit and I have had the car in the shop where they replace the sensor wire to the PCM. At that time, the P0122 was less frequently thrown, perhaps once a week. For the past few weeks, the P0122 is thrown at 9 out of 10 cold starts. The mechanic who worked on it before suggested that the problem may be with the PCM and not with the sensor. I checked the ground cable and the power input to the TPS last week. The ground seemed OK, once the switch was turned on, the TPS header showed that there was 0 ohm to ground and 0V. The voltage input to the TPS was close to 5V. Questions to the board: 0) Is the TPS a red herring for some other issue? 1) Is it more likely the throttle position sensor is bad or the PCM has a bad input for the TPS? 2) If I replace the PCM in this model, assuming I match up the same part number, would I need to do any programming of the PCM? I feel confident that I could replace it other wise. Thanks, Jeff

As I mentioned earlier, there was no code stored from the check engine event and each time the event happened, it ended before I could get to a place where I could disconnect the o2 sensor. jeff

After changing the PCV and cleaning the idle air solenoid valve, I had another intermittent idling/loss of power event that lasted about 4 minutes. It happened while the car was cold. what should I look at replacing next? jeff

I replaced the PCV yesterday and I have the IAC solenoid-valve off today and cleaning it. The IAC valve was covered in grime. jeff

EGRs didn't show up until 2003 models, so I don't have an EGR. I didn't notice any unusual smell from the exhaust. jeff

No, I didn't smell any 'rich' exhaust. jeff

Sigh.....this morning, the car was idling rough and bucking. At one point about 1/4 mile from my house, I saw the 'check engine' flash for 5-10 seconds. After the 5-10 seconds of flashing check engine, the entire system got better and I didn't experience any more issues today. I thought that a code would be recorded....but it wasn't....I tried to read it with an ODB2 reader which said there were no codes. I'm reluctant to think that it can be a O2 sensor or other sensors which are monitored but rather something outside the scope of the monitoring/reporting system. Responses to other questions: 1- I never smell gas 2- the engine runs poorly both at speed and idling. At speed, I experience bucking and a loss of power. The issues happen for a short period of time and the system recovers. regards, jeff

Hi Ferret, Things are getting worse. I've had a fourth event this morning after a cold start. Finally the check engine light came on so I should have a code now. This is the fourth event, two happened when the car was hot and two have now happened after a cold start. After the check engine light came on, the car ran better so I don't know if it ignores the sensor after that..... So, thats two events that happened after being warm, two events after being cold. Twice it happened when the fuel tank was less than 1/8 of a tank, once it happened with 1/2 tank of gas and this morning the tank is full of gas and it happened. regards, jeff

Hi Nipper, Thanks for the response. I'm not following exactly what you want me to do... Do you want me let the gas run down, then try to vent the tank by removing the cap if it has idling problems? regards, jeff

Hi Legacy777, I don't have a MAF sensor in the 2001 Outback. Is the MAP sensor equivalent? I purposely ran the gas very low today and I had another event with the same issue. Eventually the car actually cut-out. It was running very rough at low RPMs and better at higher RPMs. A car in front of me turned and I shifted out to neutral, once the rpm went low and the car shut-off. I was able to immediately re-start it and it ran better. I filled up at the gas station and then purchased a water removal gas treatment again. The engine seems to be running fine now. This event also did not result in a check-engine light coming on. I can't very well understand the second event when the car was cold and parked for four hours as water in the fuel tank since I had 1/2 tank of gas. This was the third event and two of them happened when I had a low tank of gas and the engine was warm. How many treatments would I expect to need if I have some water in the fuel tank? I've had lots of bad experience with mechanics, so I'd prefer to check it out myself. I'm going to borrow an OBD reader and see what I find. Regards, Jeff

Hi, I've a 2001 Subaru Legacy Outback with Manual Transmission and 2.5 litre engine. I do not have any turbo and have made no modifications to any of the components. I have about 85K miles on the car. I've experienced two issues with a loss of power and rough idling that resolved themselves after a few minutes. Both times the check engine did not come on. The first instance happened after a rapid deceleration (with less than 1/4 tank of gas), the engine lost power and recovered after about 5 minutes. This happened in the fall 2011. Recently after sitting in a parking garage for about 4 hours on a slight decline toward the front of the car. Again, the engine recovered and has been running well since the problem. In the first instance, I took it the subaru shop for help. They indicated that they couldn't do much if the check engine light didn't come on but rationalized that I likely had water in the fuel tank--since I had less gas in the tank during that incident. So I treated the tank with heet. In the recent instance I had more than 1/2 tank of gas, so I don't think water is a likely reason for the issue. The car was parked on a decline, but I've been parking on the same decline for two years without an incident like this. I've recently tuned up the car with new wires and plugs and I also have recently replaced the fuel filter. (The first incident occurred before these items were replaced.) Any ideas as to what could be the issue? Regards, Jeff