AL4 Transmission Temperature Sensor

The instructions for replacing the AL4 transmission temperature sensor is at http://www.peugeot206cc.co.uk/repair-206/206/info/gb/b2cg83k3.htm

Peugeot 206 Fuse Layout

Engine fusebox.

BSI fuses near steering column.

ECU Update

The car had an ECU update today. The engine ECU was updated first, followed by the transmission ECU. The Peugeot Planet 2000 system was used to do all the updates and diagnostics.


This is a huge workshop, which services Audis and Peugeots. Next to it is the Audi showroom, where I had the chance to enjoy the breathtaking beauty of the Audi R8. Click here for pictures of the Audi R8 V8 4.2 FSI QUATTRO.


The Peugeot Planet 2000 system is connected to the Siemens BSI receptable under the driver's steering wheel.


The original ECU software was 9 years old, and there were many new updates since then, which took quite sometime to download into the ECU.


The technician checked all the settings one by one. One interesting finding was that the ECU was still in showroom mode... so he switched it off. Showroom mode allows customers to play around with the accessories with the engine off, thereby draining the battery. He also deactivated the original radio because the car is now fitted with a non-Peugeot unit. The transmission oil wear counter was reset. Fault alarms were all cleared. Pedal teaching was performed.

After all the updates, the car feels so much smoother and responsive now, and feels to have more power too. I managed to max out the car at 155km/h and 4000rpm. In the past it could only manage 148km/h, so there is indeed a performance gain.

Throttle Body

I had nothing better to do, so I decided to open the throttle body. The engine has not been idling smoothly, so it was a good idea to open up the throttle body to check.

After opening it up, I found a layer of sticky carbon buildup around the idle air control (IAC) valve, the air bypass passage and the throttle. No wonder the engine was not idling smoothly. Anyway, a good clean with a toothbrush, cloth and some petrol helped remove most of the carbon.

The throttle body; throttle at the bottom, air bypass passage at the top, idle air control valve at the top right and throttle position sensor (TPS) at the bottom right.

The idle air control valve is cleaned. No more carbon on the valve.

Carbon removed from the air bypass passage.

A peek inside the air intake.

AL4 Output Speed Sensor

Peugeot 206 MAP Sensor

I've noticed a bit of engine oil in the air intake into the throttle body. I guessed some of oil could have fouled the MAP sensor (Manifold Absolute Pressure Sensor), perhaps causing the strange gear change problem when the engine is started from cold in the early morning.

I'm also wondering whether the blended engine oil could have caused this. Yes, in the effort to make use leftover engine oil, I've mixed several brands together. The bad thing about this now is that there's a lot of oil in the air hose from the engine to the throttle body, which should not be the case. Lesson learned, mixing engine oils is bad.

After taking out the MAP sensor, sure enough it was soaked in black gooey engine oil. Did a bit of cleaning and now it looks cleaner.

The location of the MAP sensor.

The Bosch MAP sensor.

Removed much of the oil from around the yellow blob, which I guess is the sensor.

Cleaning the sensor with contact cleaner results in better throttle response and more stable idling.

Here's other people cleaning their MAP sensor.

Dodge Cummins MAP cleaning:
http://mopar.mopar1973man.com/cummins/2ndgen24v/map-sensor/map-sensor.htm

Jeep Liberty MAP cleaning:
http://liberty.eurekaboy.com/mapsensor.htm