Gen 4 Prius "Maintenance" mode

On 2016 and 2017 models with the Entune head unit sold in the U.S., there is a Service Menu for the navigation receiver assembly that is vaguely similar to the one you describe, though it covers only the navigation and rear view monitor systems; it is not a general diagnostic or indicating system for the vehicle.

It’s also not very entertaining. The Vehicle Signal page shows battery voltage, speed, and status of logic inputs: power switch, parking brake, reverse, tail light, and dim/bright. The System Sensors Check page shows the GPS reception, status, measurement ratio, date and time, and position; speedometer pulse count and speed; and gyro sensor voltages and bearing. Other pages are for testing the knobs, switches, touch screen, microphone, etc., and to show trouble codes and software versions.

The Repair Manual gives the access procedure:

START DIAGNOSTIC MODE

[ . . . ]

• After the power switch is turned on (IG), check that the map is displayed before starting diagnostic mode. Otherwise, some items cannot be checked.

[ . . . ]

(a) There are 2 methods to start diagnostic mode. Start diagnostic mode by using either of them.

(b) Method 1

(1) Turn the power switch on (IG).

(2) While pressing and holding the "AUDIO" switch, operate the light control switch: Off → Tail → Off → Tail → Off → Tail → Off.
​

(c) Method 2

(1) Turn the power switch on (IG).

(2) Press the seek/track up panel switch 5 times and then press the seek/track down panel switch 5 times with the screen and audio turned off.​

HINT:

• Diagnostic mode can only be started if the above operation is completed within 15 seconds of the first press of the seek/track up panel switch.
• If the operation is not completed within 15 seconds of the first press of the seek/track panel switch or fails, turn the navigation receiver assembly on and then off again before attempting to start diagnostic mode.

[ . . . ]

FINISH DIAGNOSTIC MODE

(a) Turn the power switch off.​

Since it might come up in a search, I should mention that Toyota uses the term “Maintenance Mode” for a setting that keeps the engine running continuously for emissions inspection (smog check) purposes; this mode also cancels traction control, to allow for dynamometer tests. The only special display is the message 2WD MAINTENANCE MODE, presumably since emissions test facilities would use the data link connector (OBD II interface) to retrieve any other needed data.

 

Very good, I’ll see what I can do with this, I Thank You ElektroinGenie

 

ive been looking for this information too. thank you.

would tail also imply auto? off auto off auto?

also FYI, California is doing away with the dynamometer (about freaking time) on 2000 and up cars. They just read the readiness monitors form the OBD2 port now. so, at least in CA, 2wd maint. mode is kinda useless imo lol.

 

Yes, I think tail implys OFF. This is pretty much the same procedure as my 2005 and 2012. I can’t remember if Audio initiated. Also I don’t think I had to go to map display.

 

You’re welcome.

The idea is to switch the illumination circuit connected to the radio head unit, which is controlled by the TAIL relay:

​

Any two positions of the light control switch that do this will work: OFF, DRL OFF, AUTO, or DRL, and either Tail or Head:

​

Except for hybrid vehicles, there is also still a visible smoke test, though it doesn’t require a dynamometer; see section 1.3.4 and Appendices A and B in the Smog Check Manual 2013 (PDF), implementing Cal. Health & Safety Code § 44012.1.

Hopefully you’ll never need it, but inspection mode (maintenance mode) is also used when replacing the coolant and in several dozen other procedures in the Repair Manual, many related to emissions diagnosis.

 

Did do this this morning and it came right up, opened every window possible and was informed that everything is working OK, but, never got the level of the 12 Volt Bat. what did I not do?

 

Happy Thanksgiving to all.

 

Hi Genie, I see you have a 2016, have you tried this on a Prime?

 

No, my source is the Repair Manual for the Prime (RM32D0U), under Audio/Visual/Telematics: Navigation/Multi Info Display: Navigation System: Operation Check, where it says that the following vehicle signals should appear, from the Service Menu screen in diagnostic mode, under Function Check/Setting > Vehicle Signal:

	DISPLAY	CONTENT
1	Battery	Auxiliary battery voltage is displayed.
2	IG	Power switch ON/OFF state is displayed.
3	PKB	Parking brake ON/OFF state is displayed.
4	REV	Reverse signal ON/OFF state is displayed.
5	SPEED	Vehicle speed is displayed in km/h.
6	TAIL	Tail signal (light control switch) ON/OFF state is displayed.
7	ADIM/TCAN	Brightness state DIM (with)/BRIGHT (without) is displayed.

 

TY, I’ll try again.

 

Look at the thread (post 19 & 20) for US Trim Two.
Service Menu Prius 2016 | PriusChat

 

Thank You Genie, everything worked perfectly. Bat ready 13.6 volts. Interesting that there is a gyro within the navigation system. I always wondered why Prius didn’t display level, it’s sometimes difficult to pinpoint hillup
or hilldown. Andy.

 

You realize this is a Gen 4, not a Prime thread, right? Some things may work and some may be different.

 

Sorry, I thought I initiated a new thread on the Prime.

 

No worries.
I double checked after I realized my post before yours was no help to you.

 

well, the procedure was quite similar, just not exact.

 

Same with the Prius and the Prime, same but quite different.

 

Agree

 

THANKS MUCH AGAIN 2130: Tried it and worked fine, the voltage is still 13.6 as last Nov. I
believe this is the same procedure as I used for my 2005.