Not accelerating and shifts hard, TCS and Slip light is on

KYLE COLVERS

MEMBER
2002 INFINITI I35
80,000 MILES

Basically the car doesn't accelerate. When I push the pedal the RPMs get up to about 1.7 but then stop, and even when i'm pushing there is like a delay to get there. I took it to my mechanic but he is stumped. On his reader the 2 codes given are:

P0227 Throttle/Pedal Position Sensor/Switch C Circuit Low Input

P1612 NATS

But what's crazy is that P0227 code comes up twice. My mechanic knows that P0227 usually means the pedal assembly needs to be replaced but with that NATS code he doesn't know what to make of it. He says it could be the pedal or it could be the ECM/ECU. He used a voltmeter and got 5 volts on pins 106 and 98 on the pedal so he said the sensor should be working so it should be the ECM. That being said, he doesn't know for sure and since the car idles fine he doesn't know if its the ECM.

He wants me to buy the pedal, a $300.00 pedal, and $200.00 to install it to check if that's the issue and if it isn't he wants me to buy the ECM and that's another $500.00 and I have to go get it programed by a dealer. Does anyone have any advice or tips for me? Does anyone know how to check for a bad ECM? Would there be a code for that?

The car is a 2002 Infiniti I35 which is basically the same car as a Nissan Maxima.

it is important to note I had a similar issue 2 years ago. Back then switching the pedal worked and then my car worked. I switched my current pedal with the old one to see if it's the same issue and the old pedal wouldn't even rev the engine (this current one revs it to 1.7ish RPMs). This leads me to conclude my current pedal is working and there's a different issue. :/

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

Voltage to the APP isn't an indication that it works. Simply, it indicates it is receiving the power needed to work. You need to check voltages out from the APP to determine if it is working. The APP has two sensors in it that will signal different voltages to the ECM based on the pedal position. If you look at the last pic below, it shows the voltages out. Now, the 1612 (nats) which is related to the immobilizer leads me to believe the vehicle wouldn't start. At this point, it isn't a good indicator that the ECM is bad.

So what I suggest is testing needs to be done. That is the only way to confirm where the problem is coming from. I have to be honest, I suspect it is the APP, but as I mentioned, the only way to be sure is to check.

If you look at the attachments below, they explain how to diagnose the P0227. Once we confirm that isn't the issue, then we can check the ECM if needed. The interesting part about this is if it is a wiring issue, you could replace both and still have the same problem.

If you feel comfortable performing the tests below, here is a link that you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

Take a look through the attachments and let me know if you are comfortable doing them. Also, if the mechanic is suggesting to replace both because he isn't sure, start with the cheapest one first, the APP. Why arbitrarily replace both. Don't spend the money on the ECM unless he tells you it's needed. At that point, I would confirm that he is willing to not charge you if it isn't fixed.

Take care,

Joe

See pics below.

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