Hooking up a Zeitronix ZT2 wideband lambda sensor
There is a wide variety of wideband lambda sensors on the market. Of all these sensors I am very happy with the Zeitronix wideband lambda sensor and its controller. I have ran 2 of these sensors on a daily bases in my cars for years. Other sensors I’ve never mounted, so this guide is aimed solely on the ZT2. But probably reading this guide while mounting another brand of sensor will help you in the right direction.
The heart of the system is the ZT2 wideband AFR controller. All cables and apparatus are connected to this controller as described in the Zeitronix manual. I will only focus on connecting the signal harness with the rest of the car. This Zeitronix harness plugs into the controller on one side and has 12 wires that should be connected to the cars electronics. The following table is the table as given by Zeitronix for their ZT2 Model 2009 or earlier, appended with Honda circuit codes. The 2010 model is not that different, but I have no experience with the new function on pin 8.
| PIN # | WIRE COLOR | FUNCTION | HONDA CIRCUIT | CONNECT BY |
| 1 | RED | Switched power (ex. ignition) | IGP2 | split from IGP2 |
| 2 | WHITE | Wideband Analog Output | None or ELD | not or ELD to log with eCtune |
| 3 | GREEN | RPM Input. 0-12V square wave, tach signal or primary (low voltage) side of ignition coil. | ICM | split from ICM |
| 4 | ORANGE | Zeitronix Boost (MAP) Sensor Input | none | not |
| 5 | WHITE/BLUE | Warning Output (not available on oldest models) | none | not |
| 6 | YELLOW | Zeitronix Boost Sensor +5V Power. Connect ONLY to Zeitronix Boost Sensor RED. | none | Not |
| 7 | BLACK | Power Ground | PG2 | split from PG2 |
| 8 | BROWN | Only 2009 and earlier: Sensor Ground (EMS ground reference) | SG2 | split for SG2 |
| 9 | PURPLE | Simulated Narrowband O2 Output (for your stock ECU) / Linear Wideband Output | none or PO2S* | See note below* |
| 10 | GREY | Throttle Position Sensor | TPS | split from TPS |
| 11 | BROWN | Sensor Ground (Boost Sensor ground reference) | none | not |
| 12 | BLUE | User Input 0-5V | MAP | split from MAP |
*Note on narrowband simulated signal. Here we have two options. Either measure and datalog with the wideband sensor, while keeping the original lambda sensor in its place and function. Or replace the original lambda sensor entirely. In the first case we do nothing with ZT2 pin 9 and leave it unconnected. In the second case the ZT2 pin 9 wire should be connected to the PO2S wire of the ECU. Except this time we do not split the PO2S wire like all the others, but we cut the P02S wire. The PO2S wire running to the ECU is connected with pin 9. The PO2S wire running into the engine bay should be isolated or removed. That part is useless now.
Note on the RPM, TPS and MAP signals. As far as I know these signals are features of the ZT2 so you can nicely datalog these very valuable sensors while driving. But these signals are not required by the ZT2 system to operate normally. The MAP sensor is not even recognized as a MAP sensor, it is just a 5V signal to the ZT2 which has no calibration. So, you will read 2.90V instead of 100 MPa for instance. But connecting and using these signals on the ZT2 unit is very easy and useful to do.
For explanations and locations of the Honda circuits I refer to my pinout schemes which can be found in the menu bar.
Please, send any questions and/or remarks to me.
Dodo Bizar