Code P0845 with no flashing D light?

Tiny
ALOHA168
  • MEMBER
  • 2002 HONDA CRV
  • 2.4L
  • 4 CYL
  • 2WD
  • 208,000 MILES
Replaced 3rd gear sensor and 3.1 quarts of transmission fluid. I did not clear code with scanner or disconnect battery due to losing I/M readiness (for smog check). Just kept driving and hoping for ECM/PCM to clear the code with no success for 2 days. What should I do next? My registration/smog check is due in 3 days. How long will ECM take to clear the code, or I'll have to manually clear it? The car/transmission runs fine with no shifting problem other than that. I forgot to add that, the new and the old sensors both behave the same. Replacing the sensor didn't help. I bet the old sensor was good. Also, the number of DTC codes displayed in the scanner is 1(1 in red color) which I've never seen before. I removed the new switch and tested for resistance between the single pin and the body ground and I saw an open, I got the same result with the old switch as well. Is this switch a NC(normal close) or NO(normal open)?I've seen some online with 0.5Ohm when measured. If it's NC, then both switches are bad.I also tested the single wire plug lead with the engine ON/OFF.I got 5V with engine on and nothing with engine off. Does this narrow down to the switch itself?I can't think of any other components that can cause this P0845 code. Also, no visual 'check engine' light displayed on dashboard. I can only find out with an OBD2 scanner. Please help.
Wednesday, February 22nd, 2023 AT 9:12 AM

7 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,271 POSTS
Hello,

P0845 abnormal voltage reading from the transmission fluid pressure sensor. Once the repair is made you must clear the codes using a scanner. So, the sensor you replaced was it the transmission fluid pressure sensor? Here is the location of the sensors (there are two of them) to confirm the correct part was replaced. If so, check the connection because this could be the problem as well. If both have been done it could be the pressure regulating solenoid. Please check the images below to see what I am talking about and get back to me.

Here is how to clear the codes:

https://youtu.be/ahK_eucFi-k
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Thursday, February 23rd, 2023 AT 9:18 AM
Tiny
ALOHA168
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  • 52 POSTS
My actual reading from my OBD2 scanner was:P0845 Generic Current, Transmission Fluid, Pressure Sensor Switch B Circuit. Upon research online, I found the switch(sensor) was the 3rd gear sensor with part number 28610-RKE-004 which is located right next to the Transmission dip stick in the front.I also found online that this sensor is NO(normal open) which is what I measured with a multi-meter on both old and new. Since it's no, there is no way to tell with a meter without engine running.I installed the new sensor and drove the car for 2 days and the DTC code is still there.I have ordered a genuine OEM sensor and it's on the way. My questions are:Did I replace the correct sensor?If I replaced with a known good sensor, do I still need to manually clear the DTC code? I would like to let the car's ECM to detect the good signal and clear the code, I just don't know how long it'll take.I'd like to keep the I/M readiness for my smog check. After trying these, then I'll get into the solenoid which I hope I don't need to.
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Thursday, February 23rd, 2023 AT 9:49 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,271 POSTS
Yes, you still need to clear the codes for the system to reset. Please check the images above to see which identifies the correct sensor. Once completed you will need to drive the car through a couple of driving cycles for the monitors to reset. Engine hot then allowed to cool completely and then again hot and cold. It takes about 30 miles of back-and-forth engine hot and then cold.
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Friday, February 24th, 2023 AT 10:50 AM
Tiny
ALOHA168
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  • 52 POSTS
Okay, I will reset it after I passed my smog check.I suspect the P0845 was caused by dirty transmission fluid which I already replaced and the car shifts smoothly.I think this code is controlled by the TCM, not the ECM.I took the car for smog yesterday and it failed some small emission items(PCV and some hoses) but the P0845 was not shown in the CA DMV system?I will fix these items to pass the smog and I'll reset the code after that to find out if it will come back.
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Friday, February 24th, 2023 AT 12:06 PM
Tiny
KEN L
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  • 50,271 POSTS
Sounds good, please let us know if we can answer any questions you may have.
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Saturday, February 25th, 2023 AT 12:37 PM
Tiny
ALOHA168
  • MEMBER
  • 52 POSTS
I replaced the PCV valve and hose plus some small emission hoses and took it back for smog retest and I passed. I cleared the P0845 code with a scanner and drove for a few days and the code did not come back. I guess the P0845 code for my car was due to dirty transmission fluid. The one with the flashing D is for the actual sensor. And the code needs to be manually reset. Also, this code is not picked up or ignored by the CA DMV computer. Thank you Ken for your replies.
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Friday, March 24th, 2023 AT 12:19 PM
Tiny
KEN L
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Thanks for letting us know, we are here to help, please use 2CarPros anytime.
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Sunday, March 26th, 2023 AT 12:29 PM

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