feltf4

With apologies if this has been answered, but I couldn't find it. I have a 2003 CRV EX with MT with approximately 95K miles. A month ago it produced trouble code P0122, TPS low impedance. I reset the code but it reappeared. Ordered Blok TPS, installed it, recalibrated it to 0.45. After 750 miles, it's now giving the same P0122 code. I doubt it's the TPS again. Any thoughts? Is it a faulty ECU? Can I just keep resetting it? I'm getting to the limit of my electronic diagnosing ability.

LDForget

Likely faulty wiring. Low impedance means theres not enough resistance in the line, which is usually a dead short. Even though your getting .45 across the sensor, doesnt mean thats what the ecu is reading. Your old sensor was probably fine, thats why its always best to test the sensor prior to changing it.

feltf4

Roger that, and thanks for the reply. I suspected the old sensor wasn't bad, because it didn't immediately post the trouble code once I reset it, but trusted the reader (and figured based on the number of posts on Honda-Tech where others are having problems that the TPS may be bad). Any suggestions on how to trace the wiring problem? Should I simply replace the harness? I'm also not sure how I would test the TPS itself, to confess my level of ignorance.

LDForget

You tested your new sensor by setting it and reading the resistance. If your multimeter said OL (out of limits) or 0, that means there is no connection. If the resistance was really low, then the sensors not working properly. Your best way to find where the short in the wire is is to test the wire from the sensor to the firewall. Check for resistance. There should be about a half ohm of resistance. Anymore and you likely have a dead short. From there, you can either run a new wire from the firewall to the sensor, or pull the wiring harness all apart and fix it where the short is. Your call.

LDForget

I should ad, when testing the wires from the sensor to the firewall, make sure the key is out of the ignition. Disconnect the battery to be safe if you'd like.

feltf4

Thanks again. My only update is the code reader says "Low input" not "Low inpedance". If that makes a difference, let me know. In the meantime, I'll be under the hood tracing wires. Out of curiosity, how would you check the resistance on the TPS, given that it has three prongs on the sensor?

LDForget

turn the car to the on position but don't start it. Now check the voltage coming through the wire, it should be .45V at idle. If not, turn the tps sensor clockise or counterclockwise until the voltage reaches .45V. Once u reach the specific voltage tighten up the screws, and then check the voltage to make sure it's still at .45V. If it doesnt have a value anywhere near this, the tps is ****ed. The middle pin is the pin you need to probe.

feltf4

Update - I haven't had time to diagnose this issue so I took it to the dealer. I gave them all the history and of course they said that it is the TB ($1K - which I didn't pay). They also said that Honda cars "don't like" aftermarket parts. I did get the service manager to say that, as long as its running, he wouldn't replace it. The CEL now cycles on and off. I basically ignore it, other than checking it about every 500 miles to make sure it is just the TPS code. I may pull it and try to recalibrate it again (I did read that I should check the voltage at full throttle).

LDForget

Full throttle, vehicle off. lol.

feltf4

Now that's funny. That clarification might explain all the Toyota "sticking gas pedals".

LDForget

You'd be surprised at the mechanics at my shop, never mind people that arent mechanics. Lol. I always take the "assume everyone is an idiot" approach and explain everything in complete detail.