Auto Trans warning light.....AGAIN!

**1972nail** · 05-21-2017, 12:39 PM

When we bought our 2003 3.0i auto with 43K last year the private vendor warned that the trans warning light would light up occasionally but just switch off and on again and it would go away. Well, we didn't have any issues for a few weeks after purchase but then on it came and limp mode was enabled, switched off and on again - all OK.

A month or so ago things got worse and at every start up the light would come on - something had to be done! A transmission oil and filter change seemed unecessary at such low miles but that was done by my local mechanic. Smoother change and a quiter transmission but the light was just as active.

Today I decided to have a look at a few connections below the car. The main multi pin plug on the transmission didn't have the lock ring fully seated so off it came for inspection. All the connections were clean so I reconnected it and locked it fully. A bit of waxoil on the brake pipes that I could see and a general look over while I was there.

So, start up, no warning light, drive to my brother's house to get keys, stop and start up - no warning light, drive to my nephew's garage to collect an OBD11 code reader, stop and start up - no warning light, drive to the petrol station for a fill up, stop and start up - again no warning light.

When I got in the drive at home I finally connected up the code reader. Two codes were recorded, one on the engine and the other on the auto trans. Enigne - P0701 - transmission range fault - signaling that there was a fault in the circuit that fed the transmission module. Auto trans code -P0709 - transmission range circuit intermittent - signalling that the circuit from the transmission range switch was intermitently faulty - a loose connection? Should have borrowed my brother's OBD11 reader earlier.

So, here's hoping that all that was needed was the connector reseated properly!

The connector is the one for the transmission position switch, can these switches fail and if so can they be dismantled and repaired?...new ones are mega expensive for what they are.