1999 Lexus ES 300 Check Engine and Trac Off lights

  • 1999 LEXUS ES 300
  • 6 CYL
  • FWD
  • 135,000 MILES
Computer Sensor code from Auto Zone is: PO325

Probable causes listed are:

001. Open or short circuit condition
002. Poor electrical connection
003. Faulty KS

The Auto Zone clerk said the KS was a Knock Sensor.

The car usually shifts from low to high without a problem starting from a cold start, but after it warms-up it does not want to shift to the highest gear.

Under normal conditions, at 55 mph and the car is in third or the highest gear, the tach is at 2k, but when it does not reach the highest gear the tach is above 3k at 55 mph.

The Check Engine and Trac Off lights have been intermittent, but are on more often than not.

My friend, who worked for his dad in a garage when he was in college doesn't think it's the transmission and he thinks it running fine. He said he doesn't think it's a serious problem. However, I'm not so sure.

We checked the transmission level when it was warm and it was not up to the hot level. Not sure if it should be? The owner's manual gives no information about proper transmission fluid level or how to check it. Had to go online to find the answer. The fluid is not bright red. I changed it last August, then pulled a trailer from Ohio to Georgia in March. The check engine light came on about two weeks ago.

The first time it happened I pulled over to read the owner's manual and when I started the car again, it shifted fine. But after two stops, it would stop short of shifting to the highest gear at 55 mph. Most times when I stop and turn the car off for 20 seconds the problem goes away again until I stop or slow down twice.

I'm planning to change the transmission fluid tomorrow (6/09/09). One of my questions or concerns is how or if the shifting is related to check engine light. I probably should mention that I accidently ran over a five lb. Hammer on the freeway about five hours before the first check engine light and trac off lights appeared together. Not sure if that's a coincidence or possibly related. I wasn't able to avoid the hammer on the freeway because it happened in tight, heavy, rush hour traffic.

Please advise.
Do you
have the same problem?
Monday, June 8th, 2009 AT 7:14 PM

1 Reply

Hi fitnessguy,

Thank you for the donation.

Here is a description of the code and for diagnostic, a scanner is required.


Circuit Description

Knock sensors are located on either side of cylinder block underneath lower intake manifold assembly. Sensor generates voltage when engine block vibrates due to knocking. ECM retards timing based on this voltage signal. DTCs P0325 and P0330 are set when there is no knock sensor signal to ECM with engine speed of 2000-5600 RPM. DTC P0325 is for knock sensor No. 1 on right bank. DTC P0330 is for knock sensor No. 2 on left bank. Possible causes are:

Open or short in knock sensor circuit.
Knock sensor (loose).
Faulty ECM.

Transaxle & Transmission

1. Check transmission fluid with engine and transmission at 158-176 F (70-80 C). Park vehicle on a level surface and set parking brake.

2. With engine idling and parking brake engaged, move shift lever from Park to Low and return to Park. Remove and clean dipstick. Insert dipstick fully into oil filler tube. Remove dipstick and verify fluid level is in HOT range on dipstick. Add fluid as necessary.


Use Lexus/Toyota Type T-IV ATF.
Oil change refill is 3.7 quarts (3.5 liters)

Since no fault codes are found for the transmission, it most probably is a fault with the mechanical or hydraulics and the fluid change might solve the problem.

I would suggest dropping the oil pan to check/replace the fluid filter as a clogged filter can cause the problem described.
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Tuesday, June 9th, 2009 AT 11:43 AM

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