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Stereo Diagnostic Mode
February 19, 2001 - vnomura

Stock Stereo Programming

If you are having problems with the stereo try this out before you take it to the dealer.

The Toyota sound system has a diagnostics mode which will report to the dealer any "problems" which the system has experienced. To enter diagnostics turn the key to ACC mode and turn the radio off. Press and hold preset 1 and 6 at the same time. Now press the CD button 3 times. Codes will be displayed on the digital readout of the stereo. You will start with a H code which indicates a hardware piece, ie H-190 is the head unit. By pressing the tune up or down switch you can shift to any error codes that are present which will be displayed as 1-XXX where XXX is the error code. Most codes are related to major problems that would be hard to miss, like CD will not eject. However some are related to things many have noticed. Code 7, 13, and 20 for instance indicate sound quality poor in radio,
tape and cd respectively. Code 19 indicates CD skipping. Code 26, 27, 28 are general noise code indicating noise, noise caused by vibration, and noise when engine starts.

To exit diagnosis mode press and hold the CD key for 2 seconds or turn off power.

Reading through the diagnosis procedures leads you to replace head unit in nearly all of these cases which means of course that you would have to convince the dealer that it is a real problem.
The system maintains central diagnosis of the CD-changer or navigation system if installed so I assume neither would be connected via RCA. In my previous cars that had available changers it was always a 5 or 8 pin connector carrying both audio
and control information.

Codes

Radio:

1. Radio not operating when power switch to on
2. Display indicates when power on but no sound
3. Noise present but AM-FM not operating
4. Any speaker does not work
5. Any AM-FM does not work
6. Reception poor
7. Sound quality poor
8. Preset memory disappears

Tape:

9. Tape can't be inserted
10. Tape inserted but no power
11. Power but tape player not operating
12. Any speaker does not work
13. Sound quality poor
14. Tape jammed, malfunction with tape speed or auto-reverse
15. Tape will not eject

CD:

16. CD can't be inserted
17. CD inserted, no power
18. Power but CD not operating
19. Sound jumps
20. Sound quality poor
21. Any speaker does not work
22. CD won't eject

Amplifier:

23. No power
24. Power but amp not operating
25. Any speaker does not work

Noise:

26. Noise occurs
27. Noise produced by vibration or shock while driving
28. Noise produced when engine starts

Question:
when i put it in diagnostic mode i get...
1-190
2-360

pressing -2- gets me...

H360

1- 39
1- 62
2- 42
2- 62

Reply:
First set of numbers identify the components in the system. 190 is the head-unit, 360 is the amplifier. And yes the stock stereo mantains a feedback loop to get information from the amp which isn't what I expected.

The second set is the ones I'm not sure on. I don't have the book here, I'll check tonight. These may not be error codes but rather normal communication codes which fall into a different chart than the one I posted. The translation from Japanese to english for the manuals is not all that great but I've managed to figure out most of
it. I'll see if I can translate the manual given your actual results.

As a note I finally got the dealer to agree to replace my head-unit which has been giving me problems since the get-go. Found a technician who could hear the alternator noise and got it to skip
while sitting still. They have ordered me a new head-unit and it should be in soon.