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I have a 2007 RL that is having a weird electrical problem. Intermittently the AWD light comes on and puts the car in FWD. It is sometimes accompanied by the VSA, adaptive headlight, brake and any other non engine related alert that the car can think of. If I turn off the key and turn it back on the problem often goes away until the next time I drive the car. Sometimes it does not come on at all. Sometimes I cycle the key and it comes right back on. I took it to Acura and they could not figure it out. They wanted to follow their flow chart and replace the car one piece at a time until they accidentally found the bad part. Recently the outside temperature stopped working. This may or may not be connected. I disconnected the battery and let it sit an hour. The outside temperature still did not come on. The battery is less then a year old and tests good. The alternator tests good.
Has anybody had a similar problem or any good ideas where to go from here?
Check your battery cables as well - I had very similar issues and it turned out to be black cable (ground) that was just deteriorated over time.
Troubleshooting step #1: check basics before you start checking SH-AWD, VSA, and all other lights
Walt's answer isn't as dismissive as you might think. If you search old threads here, you'll find that a great many bizarre electrical gremlins in this car can be caused by a deteriorating battery, even if it isn't that old and tests out OK. It was a car with a lot of electrical toys, a test bed for Honda, and it has an undersized battery for the loads placed on it. I once tried and failed to get enough extra juice out of it to help some poor guy jump-start his car. I pre-emptively replace mine every 3 years, whether it appears to need it or not, just to save myself the potential grief.
My co-workers and I tested the alternator with both a multimeter and a oscilloscope to test ripple voltage. It was very good. We tested the battery out of chassis on a load tester. It was good. There is 1.5Ω from the battery - to motor ground. There is 1.7Ω from the battery - to chassis ground.
We are electrical engineers who were all technicians first. We are all RF specialists so we acknowledge the true acronym of FM. I have taken grief from my co-workers for doing this but I called my local Acura dealership for a new battery. They did not have any, but they were on order. It came in a couple of days ago, but I had time to get it and install it today. I cleared all the codes via the 3 finger salute. I am going out of town for the night so I have the ground unhooked and will leave it that way until I come back tomorrow. I hope this works.
I drove the RL around yesterday and the problem was the same. At least the battery is no longer a suspect. I cleaned the connectors before installing the battery.
I drove it to work this morning. It was only the SH-AWD error, which is pretty normal. It went away after a restart. The outside temperature came up for a while with -22, but went back to --- after about 20 minutes. I am happy to say that It was about 38 and rainy. -22 sounds way too cold.
I fixed the temperature sensor problem. One of the wires was broken at the connector the sensor plugs into. I soldered it up. It works like a champ.
I also cleaned all the relays and fuses in the fuse box under the hood. There was no resistance between either the positive or ground from the battery to the ones in the fuse box.
The sensor is located behind the grill just to the side of the front license plate. It is clipped in. I stuck my fingers through the slots in the grill and managed to unclip it and pull it through the grill to see the broken wire. It is all clipped back in and a picture does not show it.
I pulled the sensor through the grille but the wires look good. What else can cause the sensor to not work? I have no other electrical issues, except the HFL that draws 0.22 amp with the ignition off.
The sensor's continuity tested 1.75K ohms at room temperature which I think means it's working. Are there anything else to test for, maybe a fuse? The A/C and auto climate control works as expected, but the outside temp gauge reads --- aka flatline.
02-25-2020, 06:15 PM
