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Suzuki Verona 05 P0121

Maintenance/Repairs
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#1

I asked a question here previously, and you guys were able to help me solve the problem. Well, I have one more thing I’d like some advice on.

My 05 Suzuki Verona has the check engine code P0121 ( http://www.obd-codes.com/p0121 ). Now… my throttle body assembly was replaced about a year ago, and the warranty is up in about 3 weeks. I took it to the mechanic who originally installed this part, but they said they could not find what is causing the problem (though I have a suspicion that they are sick of my car and it’s difficult-to-fix problems and did not try).

I contacted the dealer, on the mechanics recommendation, and they told me that they would charge me for the time it takes to diagnose what went wrong with the part, if anything. The lady I talked to seemed to become unpleasant when I mentioned my warranty :confused:

The advice I am seeking is what I should do now? Do I need to take my vehicle to the dealer? Is there anything I can do to fix the check engine light myself? Anything helps.

In relation to the P0121 code, I have not really noticed any performance issues with my car either, so I don’t know if there is actually anything wrong with the car. I promise I’m a nice guy who just wants the check engine codes to stop so I can pass my smog check.

#2

Didn’t you find someone who helped with your other problem on this vehicle ? If so maybe they can help on this one also. Suzuki has left the US market after all.

#3

Have you tried getting the code cleared to see if it comes back?

#4

Whoever is doing warranty work on these needs to correct the problem. As long as you have documentation that you had the problem before the warranty expired, it should still be covered after the warranty period. If this is the extended emissions warranty, they may well want you to pay for a diagnostic test to see if it is an emissions problem or not but then not charge if it is covered.

#5

If you want Suzuki to pay for warranty work, you have to go to a dealer. If the dealer you bought the car from is still in business selling other makes, they should still have access to Suzuki to cover the work. If it turns out the problem is not covered by warranty, you would be on the hook for all diagnosis and repair work. If there was work done to the car by anyone but the dealer that could be related to the P0121 issue, that might have voided the warranty. In any case, you should get it checked and fixed.

#6

Concur, if the TB is under warranty, seems to me they should fix this problem. Depends however on the wording of the warranty on whether they’ll fix it for free or not. A warranty is a legal document, and you know what that means: It all depends.

But there’s no harm asking anway. If they won’t fix it under the warranty they should be able to explain why not at least, referring to the wording of the original warranty.

If you’re more interested in figuring out what’s causing that annoying code than who’s responsible to fix it, if I had this problem here’s how I’d go about it.

  • As mentioned above, clear the code. It might go away and never come back.

  • No go? Remove the connector to the throttle position sensor and probe the terminals (of the part connected to the wiring harness) with a DVM. TPS connectors have three terminals, two (+5 volt and ground) are an input to the TPS from the ECM, the other (uncertain voltage when not plugged into the TPS) is an output from the TPS to the ECM. So one of those should measure 5 volts, one ground, and the other, doesn’t matter what it measures, it’s an output from the TPS and the TPS isn’t connected. Note: The key will usually have to be in the “on” position to cause the computer to power up that connector.

  • Those seem ok? Next, with the key in the “off” position, measure some resistances at the other side of the connector, the one attached to the TPS. If the TPS is just a variable resistor like on my Corolla, one pair (the inputs to the TPS) should have a fixed resistance that doesn’t vary with the throttle position. The other two pairs (on terminal is the output from the TPS), should vary with the throttle position, and add for a certain throttle position the resistances of the two pairs should up to the fixed value.

  • When doing the above, does it seem to check out, but do you notice the resistance go off scale briefly on occassion? If so, your TPS may just be worn out. It’s behaving like an old radio, you know where you turn the volume knob and the sound goes away briefly, then you turn the knob some more and it comes back. Bad spots on the variable resistor.

#7

If the throttle body was installed and purchased through your independent mechanic, the dealership has nothing to do with the warranty. Perhaps you could clarify.

This shouldn’t be rocket surgery to diagnose. Always check wiring and connections before replacing a sensor.