i can tell you which one it's not and that is the black with white stripe that one is a ground.hope this helps at all.
there are 2 oxygen sensors on your vehicle. The first is located close to the engine, in the exhaust pipe. Look for the wire that leads to it, that will help you find it. The second is right after the catalytic convertor. Again, look for the wire that leads to it. The both come out by turning it counter clock-wise. Disconnect your battery, unplug the wiring harness to the oxygen sensor and remove it. After you put the new one in, re-connect the wiring harnes and re-connect your battery, and your done.!!
Often the MAF sensor needs replacing, or possibly the coil packs, leads, spark plugs, K40 relay board (re-solder or replace), oil contaminated wiring, O2 sensor or crank angle sensor, disintegrated vacuum hoses, loose hoses, other.
It could be a number of problems. It could be the sensor is bad, it could indicate a fault with the alternator, faulty leads, faulty wiring... it depends on the situation.
On 1.8T motors the engine speed sensor is on the lower part of the engine block on the driverside. It is held in my one Allen head bolt. It should have about a foot of cable which leads to where it plugs into the wiring harness of your car under the intake manifold.
The return hose for the heater core generally leads back the the water pump. The inlet for the heater core comes from the engine.
Generally, the upper heater hose leads to the water pump.
The hose that leads to the water pump area is the return.
From the bottom of the motor contactor's heater block you connect the motor's leads to T1, T2 and T3. If the motor rotates in the wrong direction reverse any two leads on the bottom of the motor's contactor heater block.
If you look at the Drivers side of the motor you will see a wire that leads in under the intake. That wire leads to the knock sensor. The plenum, fuel rails,intake and thermostat housing will need to be removed to get to the sensor.
Its under the cowl in engine compartment (close to windshield) in one of the heater hoses that leads to heater core. Black and white plastic with a small vacuum hose attached to the top.
P1646 is a fault in the heater or sensor of the upstream O2 sensor. It is the light grey plug on the firewall behind the engine and leads to the sensor unit itself on the rear bank exhaust pipe. A replacement sensor is between (UK) £65 and £120 depending on where you go. Beware of the generic 4 wire sensors as their specs are not quite up to Jaguar's. BTW. It's a b*tch to get to and you need a 22mm socket with a slot for the wires to go through.
buy the "Lisle Tool Heater Hose Coupler Remover #62200" from a parts store like Advance