Audiovox Prestige APS57TM Tach Sense Won’t Program

I’ve just installed an Audiovox Prestige APS57TM in my 2015 Toyota Tacoma Access Cab SR5 with 80-bit G key. Used a Fortin KEY-OVERRIDE-ALL that programmed first try. All connections soldered. Connected the Prestige green/orange wire to the black/white wire off the OBD II connector. Tach won’t program. I’m following the procedure in the install manual. Looking for a workaround that others may have used. Whatcha got?

The programming on the system Bank 3 Option 5 is Tach. When I push the remote start button twice I get 7 flashes of parking lights. Tach not learned. Looking for other places to connect the tach wire. In the install instructions it says to go to the engine compartment and verify with DMM. I will if I need to but was hoping to find a location in the cab. Thanks.

Just checked the wires. DMM on AC pos lead to vehicle +12. Neg to OBD pin 9 black/white. 0 volts with truck off. Start truck, about 7.5. I checked the same at the RS module to be sure the wire wasn’t broken. Circuit is good. Thing is, as I rev the engine, the voltage barely changes. I mean maybe a couple tenths of a volt over a few thousand rpm. So depending on how the RS is sensing, this may not be enough to learn the tach. Still looking for an alternate location for the tach signal but looks like at this point I may need to switch to voltage for engine confirmation. If I do that, it looks like the voltage level (bank 3 option 6) would need to be set to <0.5 B4 Start. Can anyone confirm?

Possibly a dumb question but did you perform the Tach Learn process successfully? excerpt from 57E guide... 2) TACH RATE SETTING: 1. Turn the ignition key to the On position. 2. Press and release the valet/program push button switch 3 times. 3. Immediately turn the ignition key Off. 4. Press and hold the valet/program push button switch, then start the vehicle using the key. 5. When the unit senses the tach signal, the parking lights will begin to flash. 6. Release the valet/program pushbutton switch. The parking lights will turn on for three seconds to indicate that the learned tach signal is stored and the unit is out of the tach learn mode. NOTE: If the unit fails to learn tach rate due to an improper tachometer connection or a poor tach source, the parking lights will not flash. To correct this situation, locate and connect the Green/Orange Wire to the proper tach signal, and then repeat the tach learn routine. Not sure if this is the same as your 57TM process. Do the Parking Lights flash while the button is pressed? Do the Parking Lights turn on for 3 seconds after you release the Valet/Program button? Think I remember that you should have the engine warm and actually hold the button for over 10 seconds. Some Toyota's have a Tach signal at OBD2 Pin 9 and others don't. Usually, the 4 cylinders do and the V6's don't or visa versa... Last resort is a Spark Plug Coil or Fuel Injector. Use the odd colored wire.Soldering is fun!

kreg357, Thanks for the sanity check. That is the same procedure as the 57TM. I’ve tried it multiple times and it doesn’t blink the lights. Tried holding it for 30 seconds and it still doesn’t flash. Think my next step is to run the wire to a coil. What do you mean by odd colored wire?

Typically there are two wires at each F.I. or Spark Coil. One wire will be the same color on all F.I.'s or coils. The other wire will be different on each. Use that different color wire. You can test with the DMM but the AC reading will be lower, around 1 volt.Soldering is fun!

Just to close this up for anyone with the same issue. I changed the settings in Bank 3 to Feature 5: Voltage (2 chirps/blinks) and Feature 6: <0.5 B4 Start (2 chirps/blinks). This works perfectly. Started right up. My initial concern with using the voltage was based on others’ reports of having trouble starting while ambient temperature is cold. But knowing that in my truck the voltage goes from zero to 7 makes me believe that it will be fine. If for some reason that changes come next winter, I’ll come back on and update.

you sure the wire you were testing was BLK/white and not white/black? also shouldn't it be negative terminal to ground, and positive lead to the wire you were testing?