search terms : O2 AFR Diagnostic, Wireless Wide Band AFR Meter, Wide Band Air Fuel O2 Controller, Wide Band O2 Sensor, Bosch LSU 4.9 O2 Sensor, Bosch LSU 4.2 O2 Sensor, Bosch Cj125 O2 Sensor Controller, Arm Cortex-M3, LPC1347,

Bosch Wide Band O2 Sensors :

For more details please visit our wiki.efiHacks.com.

Our efiO2Meter  is designed to interface to 2 different types of Bosch wide band O2 Sensors. We only recommend to use the newer, more robust and faster Bosch LSU4.9 type (Bosch USA # 17025) over the older Bosch LSU4.2 type.
Yes, it cost’s a couple bucks more, but keep in mind that the LSU 4.2 was almost the very 1st Bosch Wide Band O2 Sensor and the LSU 4.9 could be seen as, that it most likely incorporates everything that wasn’t ideal in the 1st designs to begin with. We like the hindsight improved version :)

We have found a very nice Comparison of the LSU 4.9 vs LSU 4.2 at
Since we do not want to copy other peoples stuff, let’s hope that this link will last a while.

Another convincing example of comparison are the measured Lambda calibration reference points for each sensor, taken from the original Bosch Sensor Data Sheets.

Bosch LSU 4.9 : a total of 25 data points

0.650, 0.700, 0.750, 0.800, 0.822, 0.850, 0.900, 0.950, 0.970, 0.990,  1.003,  1.010, 1.050,
1.100, 1.132, 1.179, 1.429, 1.701, 1.990, 2.434, 3.413, 5.391, 7.506, 10.119, 30.000

Bosch LSU 4.2 : a total of 10 data points

0.700, 0.800, 0.850, 0.900, 1.009, 1.180, 1.430, 1.700, 2.420, 30.000

While we offer these sensors through our eShop, we do not keep their manufacturer and part numbers a trade secret. If you feel like it and search the web for a less expensive sensor source … please feel free and we will not be disappointed. Make sure it has a connector which is supported by us or you have a source for it. We’re in the business to sell our high tech circuit board based devices, offer the approved sensors, but only ask you to buy the, to you, important items from us.

This module uses The Bosch CJ125 highly specialized wide band O2 Sensor front-end processor. It controls most of the sensor  operations and an 32-bit ARM CPU does the rest.

please use our wiki.efiHacks.com page for more details on this product and more …


Sensor and Connector Part Numbers :

While we offer part numbers and alternative purchase sources as a courtesy of our Open Interface /  Information Policy, we can not be held responsible for errors in our documentation or misunderstanding of the, from us provided information.

These sensors come in all kind of flavors, i.e. cable length and connectors. The, from us documented sensor part numbers and in our eStore sold parts should match the, from us published connector part numbers and in our eStore sold connectors.

While some of the LSU 4.9 connectors look alike to the LSU 4.2 connectors, they are absolutely NOT interchangeable … their sizes are significantly different and so are their electrical properties !!!

We do not have any business affiliation with the, on our website mentioned 3rd party parts links …, however, if you decide to purchase from any of our documented links, please find a way to convey with your purchase (email, ecomment, enote,…) to your purchasing source that we recommended you. This way there might be chance for us to get the parts from them at a discount and eventually you might be able to purchase it in the future at a more competitive price from us.

Bosch LSU 4.9 Sensor :

5 Wire Wideband Oxygen Sensor

Bosch 0 258 017 xxx

It appears that the 017 in the 10 digit part number designates the 4.9 type of sensor and the xxx stands for the cable length and possibly a difference in the connector.

Bosch 17025,  0 258 017 025
Bosch OE # 0 258 017 025 ( 0258017025 )

cable length 3 ft.

source : OxygenSensor.net

Bosch LSU 4.9 Sensor, FoMoCo :

5 Wire Wideband Oxygen Sensor

# 8F9A 9Y460 EA B556D
Bosch 0 258 017 262 / 263

cable length barely 1 ft.

sources : various

Bosch LSU 4.2 Sensor :

5 Wire Wideband Oxygen Sensor

Bosch 0 258 007 xxx

It appears that the 007 in the 10 digit part number designates the 4.2 type of sensor and the xxx stands for the cable length and possibly a difference in the connector.

Note : we have not verified all LSU 4.2 documented part numbers.

Bosch 17014, 0 258 007 014 ( 0258007014 )
Bosch 17018, 0 258 007 018 ( 0258007018 )
Bosch OE # 0 258 007 057 ( 0258007057 )
Volkswagen # 021-906-262B

source : OxygenSensor.net

Bosch LSU 4.x Type Connectors :

For the connectors we have not really found a One Stop Single Item Purchase Parts Source, sorry …

Also there are just sooooo many confusing and misleading numbers floating on the NET … we even had problems of sourcing the right parts :)

Also … please don’t ask us if any of the connectors and crimp contacts you found would fit, unless it has a very convincing price tag and lots of info along with it, so that we’ll be able to also source it from there and finally offer it in return at this reduced price. Those connectors are just a few bucks compared to the rest, so take it easy and buy it from us :)

To add to the Mystery and Confusion over part numbers, the Bosch Connectors require Bosch Crimp Contacts and the FEP Connectors require Tyco / Amp Crimp Contacts.

As example, the Tyco / Amp Crimp Contacts fit perfect into the FEP Housings as intended, but the fit too loose into the Bosch Housings and slip in slightly rotated not aligning properly.

Due to the lack of Bosch Crimp Contacts We have not tried it the other way, but assume they will not fit at all.

LSU 4.9 Connector :

Bosch 1 928 404 669

FEP  42121700

Tyco / Amp Crimp Contacts 969019-2 or 964275-2

1J0 973 713 – 6 Way Sealed Female Connector 1.5 mm, 2-row, Coding I

others :  1813139-1 Mates with : 42064700

LSU 4.2 Connector :

VW # 1J0-973-733

FEP  42122200

1J0 973 733 – 6 Way Sealed Female Connector 2.8 mm, 2-row, Coding I

others :  1J0 873 733 Mates with : 1J0 873 833

About Wires and Cables :

The Automotive Environment is not like a walk in the park at moderate sunshine and therefore some precautions should be taken to match those automotive requirements. Typically one of the worst are the heat and possibly chemicals in an engine compartment.
The other is the electrical noise on almost everything electric in a car.

We found also a nice article describing some of it at
http://www.kayjayco.com/techGeneral.htm and

Cross-Linked Polyethylene wire :

For our applications we use strictly the XPE Type Cross-Linked Polyethylene wire insulation, wherever possible.
Environment specs are -51°C to +125°C, Engine compartment wiring,

The correct wire is Type TXL, Thin Insulation Thickness since the average voltage being carried is typically 12 V with peaks up to 40 V. You don’t need too much insulation, and no one handles these wires daily like the cord of a blow-dryer or electric power tool.

Also to keep the controller sizes small, especially for motorcycles, the connectors are small as well and we need thin insulated wired to fit the connectors.

Shielded Multi Conductor Cables :

We offer the Belden 6 conductor shielded cable, Part number 8786 060500 if you want to know more about it … it’s about $ 2.00 per foot and the min quantity is 500 ft, about 1 k $. Unfortunately there is nothing available with multi-conductor and shielded in XPE type insulation.

Connector Handling :

If you crimp your wires and assemble your connectors, we got a copy of the FEP Sealed Connector Manual  for you.