Hey guys I got a 2002 Nissan Frontier supercharged. So I replaced the TPS because of a fluctuating idle RPM. I fixed that problem but now it’s throwing a code for p0122. I cleared the code with a scanner tool but every time I test drive the service engine light turns on and throws the code. Anybody know whats the problem or where I went wrong in replacing it?
On many vehicles there’s a TPS relearn or reset procedure required after changing the TPS. I don’t know the procedure on yours but willing to guess that’s what you need.
Did you properly adjust the TPS ? or just bolt it on ?
Are you thinking of TPMS for the tire pressures? O.P. is referring to throttle position sensor.
This is a dual sensor for safety and one of yours has low voltage. Since this is a new part and only one code is thrown, this likely cauxed by a broken wire or a corroded connection. On your code scanner see if you can read the voltage from each of the 2 sides of the sensor. If one shows low or zero, that confirms the problem…start searching for the worn wire.
No I’m referring to the throttle position sensor.
I adjusted it.
Ok I’ll try to look it up the procedure
1 Like
Good ideas above. If those don’t pan out: Can’t speak to the tps sensor design used on your truck, but on my Corolla it has switches which detect the idle position, and wide open throttle. Those settings have to be adjusted using an ohm-meter while adjusting some screws for it to work correctly. For example if you drive the car and it never registers on the idle setting, the computer may flag that something is wrong.
Ok I checked the voltage on the old TPS and the new one. Says 0 for both. I must’ve damaged a wire or something when changing it out. When I find the wire, how do I fix it?
When you find the wire it will be obvious how to fix it. Reconnect it, replace it, install a new connector ect. Also make sure there is a proper ground, too.
If both show 0, how is the truck running at all? If you press the pedal, does the vlotage rise on each signal?
The voltage doesn’t rise. No response just stays at 0.
I think it would still run without the tps working. After all the throttle plates are still opening and closing I presume. The computer would be a little confused is all about how to set the fuel injection volumetric rate. This would probalby show up as symptoms more on rapid accelerations, maybe get some backfiring on decels.
Your tps probsbly requires a precision voltage reference as an input, often 5 volts. If that’s at zero volts you won’t get any reading out of it, but that wouldn’t imply the tps is faulty. That’s where I’d look first.
1 Like
Can’t find any damage to the wires. I’m guessing it’s the connectors so I’m gonna try to get a pair and replace them. I’ll let you guys know how it goes
Sorry forgot to update you guys. But I changed the connectors to the tps and it still throws the code. I didn’t have the time to search through the wires so I brought the truck to a Nissan dealership. Been in there for 3 days and they update me everyday. They can’t seem to pinpoint what’s throwing the code. Wondering if anyone has had a wiring issue with the tps?
I’m going to be a sourpuss here . . .
The guys at the dealership are probably recent UTI “graduates”
Usually not the best ones to diagnose and fix a drivability problem
I’ll go even further . . .
Since this seems to be a hard code, if they can’t figure out what is setting the code, the guy working on it might be simply incapable of figuring it out at this time
Any good and experienced mechanic with the wiring diagram, fault setting parameters, shop manual, dmm and common sense ought to be able to figure this out in short order
The dealership is not always the best place to bring a vehicle for diagnosis and repairs, especially ones that’s almost 20 years old
4 Likes
I completely agree. They claim to be certified Nissan mechanics but no technician can figure it out. I’ll update you guys with what they tell me tomorrow and you guys can tell me if you think it’s bs. Thanks for the input
1 Like
Is this a 6 pin TPS or a 3 pin TPS? If a three pin, one pin should have a constant voltage, one pin ground and one pin with a variable voltage as the throttle is actuated. Un plug the TPS and look for a voltage on one of the pins, the other two will be zero when disconnected.
If it is a six pin TPS, then three pins are for the actual TPS. The other three are connected to a supply pin and the other two are connected to a wide open throttle switch and the idle position switch.
1 Like
Ask your shop whether they’ve verified (1) the precision voltage is present at the connector; (2) the ground is present; and (3) there’s variable voltage present that changes in the expected manner as the throttle is moved. The same for the open throttle switch and idle position switch, have those been tested? if applicable.
Might be best to just ask them question (1). If they don’t know if that’s been tested or not, not a good sign.
Sorry for the long update. But they found a damaged wire somewhere in the harness. Don’t know why it took them so long to find it but whatever. Thanks everybody for the help. On to the next problem with this truck 🤦🏽
3 Likes