After witnessing a flashing “D” in the transmission display, I ran codes with the BlueDriver and found that code P0847 was stored. This is the “3rd clutch transmission fluid pressure switch,” per the service manual. And fortunately, the manual reassures us that this cannot be a mechanical problem inside the transmission, but is an electrical problem with the pressure switch or its related circuit.
In the DTC troubleshooting chart, we see that P0847 results in blinking “D” indicator, but the MIL (malfunction indicator light, aka check engine light) remains off.
The factory service manual shows the pressure switch to be located beneath the battery tray.
So thankfully, we don’t have to worry about there being a mechanical issue with the transmission. Aside from checking the harness to make certain the wires are not shorting out to ground, replacement of the switch should cure this issue.
The Honda part number and description are apparently “Switch Assembly, AT Oil Pressure (Saginomiya) – Acura (28600-RCL-004).” This is assuming that part #9 and #13 in the illustration below are the correct item. (As you can see above, the drawing in the service manual is somewhat vague.) Fortunately it is a common part, and the same part number is used on 2.4L Accords from 2003-07, the CR-V from 2003-2011, and the Element from 2003-2008. Online discount Honda parts dealers are around $60 for this part. There are aftermarket knockoffs for far less, but I don’t trust the quality of those.
