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355 Posts
J35 TB Calibration Process

It doesn't mean much now, but my recommendation would have been that if you weren't throwing the P1683 code, avoid the calibration procedure, since that's what it was meant to correct.
I would think that if the ECU programming is stock, then the low idle may have to do with dirt or a blockage in the throttle body. Just a thought.
I need help. I bought a J-35 TB from AHParts in CA, and I also have a FlashPro, and I'm currently in the process of eTuning my Hybrid Racing CAI with VitViper.

I currently have my stock OEM TB installed because I couldn't get the J35 TB to play nice. Maybe my expectations were too high, but when I installed the J35 TB, I got a huge rev bounce from 1500rpm to 3200rpm.

When I started the install of my J35 TB I went through the relearn process by disconnecting the battery for at least 15mins (during the TB install) which was long enough for the Navi code being required to be entered, and when I fired it up, the car idle bounces from 1500rpm to ~3000rpm. I tried giving it throttle and hold it at 3k as best as I could for 10 mins, and all I experienced was smoke coming from the motor. It smelled like a BBQ, not kidding... I assume I was running super rich due to the larger throttle body....? I could not tell if my rad fan kicked on or not, but when I see smoke, I panic.

I'm running the first revision of my tune calibration, but I'm reluctant to send the datalogs as I drop up to my GF house in Los Angeles because I could only get the car to run the CAI with the stock TB installed... :sadface: I really need to send a data log with the J35 TB installed so the tune is more accurate.

I don't have a multimeter yet, so I think I'll go to Micro Center that's by my office, and pick one up. Do I stick the leads inside the where the wires connect to the male plug while the ignition is on?

Please help!?!?!

158 Posts
Not trying to bring anyones day down, but...


"Since people often swap to larger drive by wire throttle bodies, we tested Civic Si, TL Type S and ZDX throttle bodies for compatibility.

There are two types of drive by wire systems that Honda uses. One where the ECU drives the throttle body directly (Civic, TL, RDX) and where there is a separate throttle controller (S2000, TSX before 2007).

ECU driving the throttle body directly.
throttle-civicsi.png (13.76 KiB) Viewed 7968 times
ECU communicating with the throttle controller.
throttle-tsx.png (30.88 KiB) Viewed 7968 times
All throttle bodies have two components - a DC motor to position the throttle plate, and a throttle position sensor to determine where the throttle plate is. The throttle position sensor has two resistive elements (A & B) for multiple redundancy. The motor is driven both open and closed by the ECU or controller, switching voltage across the motor using two sets of transistors.

Tests - Throttle Position Sensors

1. TPS A & B voltage
A. Civic Si
Closed 0.60 / 1.48 volts
Default position 0.85 / 1.67 volts
Open 4.00 / 4.20 volts
Closed 0.62 / 1.50 volts
Default position 0.89 / 1.72 volts
Open 3.85 / 4.07 volts
Closed 0.60 / 1.47 volts
Default position 0.90 / 1.72 volts
Open 3.97 / 4.17 volts

2. Throttle plate position
A. Civic Si
Closed 0.1%
Default position 7.8%
Open 105%
Closed 0.0%
Default position 9.1%
Open 100.3%
Closed 0.1%
Default position 9.5%
Open 102.6%

The TPS sensor for each throttle body works in the same way. The default position is different for the TL & ZDX throttle bodies.

Tests - Motor

1. Motor resistance
Averaged over 6 measurements, open direction and closed direction, using actual current for set voltage
A. Civic Si 2.85 ohms
B. TL-S 1.70 ohms
C. ZDX 1.35 ohms

2. Peak current @ 14V
A. Civic Si 4.9 amps
B. TL-S 8.2 amps
C. ZDX 10.4 amps

As the throttle body gets larger, the motors are higher torque / higher current. This is not proportionate to the throttle body opening area, as the ZDX throttle draws almost twice the current of the Civic throttle body.

Under real world conditions the throttle controller will vary the current to the motor in order to position the throttle plate. The current required to do this will be around the same for each throttle body (roughly 1 amp). However, the peak current is much higher on the larger throttle bodies. This is likely to be a problem if the transistors in the throttle controller shut down from over current or over temperature.

With the Civic Si / R18 ECU, the throttle controller uses a IC chip to drive the throttle body motor. The IC is rated at 5.0 amps continuous current, and has over current and over temperature shut downs. Switching to a throttle body which uses more than double the current is likely to overload the controlling IC.


Bigger throttle bodies draw more current, potentially overheating the controlling circuitry, causing erratic throttle operation and errors. This cannot be fixed by software."

Pictures are in the link above.

TL;dr: Our throttle controller isn't equipped to handle the bigger, more badass throttle bodies.

Potential work around? Swapping motors on throttle bodies. Don't have any lying around to test that, but...

355 Posts
So I was tinkering around with the TB. And after rereading this thread I learned that I had to adjust the threaded Allen screw next to the black motor assembly. The Allen key didn’t budge it. I tried PB plaster, nothing. So, I put my impact drill on it to hopefully back it out. Nope. I snapped the bit off inside the Allen screw head. So, now I have a useless TB. Thanks Honda!!! ?

32 Posts
I wanted to try to bore my J32 so I did. Not a good result. A friend of mine was selling a J35 tb but I'm that can of ''do everything by myself'' guy. I brougth the tools and machine a base to fix j32 tb to my table, also I did a base to make my 64mm plate. I did 5 plates to check wich one was the correct... then I installed everything back together but iddle was bad and CEL came on. I did all the steps here described, also the voltimeter test but P2101 code still on the dash. P1683 code just appered once. Next step is to go back to install the plate that gives me P1683 and try, but if it does not work I definitely will get a J32 again. If someone knows how to make it work I will appreciate. Thanks.



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