HyBruce

Newly Replaced Intelligent Power Module (Ipm) Affecting Fuel Economy?

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Finally took my 2006 400h to the dealership for the recall of the Intelligent Power Module (IPM).

Since then, I've noticed my gas mileage seems to have gone from about 22-23 miles per gallon to 18-19 miles per gallon.

When I dropped it off at Lexus I had joked with the service person "since this controls the hybrid system, maybe my fuel economy will improve." Little did I know it might affect it the other way!!

Has this happened to anyone else? Does anyone know anything about this?

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they need to do the ISC reset....take it back....or research this forum for the procedure.....

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Agree with the above. The battery would ahve been disconnected for them to work on the vehicle and they havent done the ISC reset. The may not even be awsre of the TSB or (as someone else experienced) they may be toally inept - someone had a service manager tell them the ISC is self initiallizing...it's NOT. You could try it yourself or just print TSB and ask them if they did it/demand that they do it. By the way, that TSB is dated 2006 but there were identical TSBs issued for 2007 and 2008 models.

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Thanks to everyone for their input!

So I tried to do the ISC reset on my own, never seemed to work. So I took my Lexus back to the dealer. They said the ISC reset can't be done on my hybrid, it doesn't apply to hybrids or something. So basically they checked the car out and said it might be my tire pressure was low and the fact that I'm not using the highest grade fuel. This is pretty much nonsense since I've been driving and fueling my car the exact same way since I owned it, and the fuel economy didn't change until after they replaced my IPM. I agreed to try a few more tanks of premium gas and keep track of my mileage for them. And when I get the same results? THEN what? Very irritating.

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Just further proof that they didn't do the isc reset and don't know what they are doing. Did you print the .pdf file from here and show it to them?

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It boggles my mind how little these "expertly trained" dealer service techs and managers know about the cars they work on.

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okay I'm an airhead and I hadn't noticed the PDF someone was kind enough to link to before, but I do now and will be taking it to the dealer this week!

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HyBruce,

I have a 2009 Highlander Hybrid and had the IPM replaced (per the recall) in Nov 2013 and I have noticed a 5 - 6 MPG drop since. I have found other HH owners with the same problem on another forum. The IPM in the Lexus is the same as in the HH as the most recent recall is affecting the 2006 - 2010 HH's and the Lexus RX400h 2006 - 2008. The dealer tells me that the IPM has nothing to with gas mileage and the winter months are affecting my MPG. I say BULL! Not 5 - 6 MPG drop because of winter. Our average winter temp here is about 45F. I have recently filed a complaint with the NHTSA, but have not heard anything back yet.

TAB

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Hi Tom and welcome to the Club.

It never ceases to amaze me how much differance there can be between Lexus dealers. Having owned four Lexi, my dealer is on the mark every time. However, when you read some of the other post regarding experiances with other dealers around the country and Canada, you would think their Techs. were trained on "Erector Sets".

I have noticed that the 2013 Rx350's have been getting a lot of complaints about mileage as well. We took delivery in October of this year and MPG has been less than wonderfull.

Come back and let us know how things are going.

Paul

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I had the recalled part replaced on my '08 rx400h over a month ago, and my mileage is just as poor (still around 20-22mpg) as it was before i went in; no change. When i picked the car up, all my settings had been lost (telling me they did remove the battery), and i know they didn't do the ISC reset on it.

I've done the ISC reset multiple times on my 400h (after the battery is removed, etc) with no change in performance or mileage. Don't know what that means, though!

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After IPM module was changed my fuel economy dropped by 5 miles/gallon. I have filed complaint with lexus and they instructed me to take it to the dealer. Dealer obviously did not find any issues. I am writing to Lexus for an answer and copy Department of energy and transportation on this issue. This eventually will cost owners and impact environment.

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Ok sorry to resurrect this but I had mine done yesterday and no presets were disturbed. but what really bothers me is that I took hybrid covers off and the IPM cover does not appear to have been disturbed (road grime dust etc with no smudges) The ticket said they replaced the transistor and two tubes of grease) I hope they did not do a paper install and charge for it. Any thoughts.? Is there any way to tell if they did it.? Sorry just don't trust these dealerships. THe shop forum balked at doing the ISC reset, but I showed him the TSB that explicitly points out that anytime the battery is disconnected that the ISC should be reset. What a bunch of idiots.

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question, does anybody know if the IPM is different on the AWD versus the FWD.? My paper work says replaced ipm transistor for FWD. My car is an AWD with two motors.....

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What was the part number? My replaced IPM 'transister' was 04001-29148 and I have AWD, but it doesn't way AWD or FWD on the paperwork.

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Thank you for your response, yes Mine list the same IPM transistor. But under MYLexus site the maintenance entry shows FWD....probably a paperwork mistake.

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