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Skyvisions, ASE Certified Technician
Category: Toyota
Satisfied Customers: 14422
Experience:  Toyota Master Diagnostic
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2004 Toyota Camry, We have no codes, no check engine light

Customer Question

2004 Toyota Camry, We have no codes, no check engine light and have not replaced the battery in the last year. We took the car for emissions and it failed. It says that the catalyst and the evap system is not ready. What would cause this? We did have and teen safe module plugged into the computer, that tracks speed and driving habits. Would this cause the computer to no read correctly?
Submitted: 2 years ago.
Category: Toyota
Expert:  Skyvisions replied 2 years ago.

IS the car other wise running normally?

Customer: replied 2 years ago.
Expert:  Skyvisions replied 2 years ago.

Is this a California specification car or do you live in New York or California? Are you aware of the particular drive cycle that you have to drive in the temperature ranges the car has to be in order for the monitor test to pass?

Customer: replied 2 years ago.
This is in Arizona. We stopped by the Toyota dealership yesterday and they told us to drive for 20min @45mph and 30min @ 55-60mph. We have done this, we actually put on over 120 miles at various speeds and stop and go traffic. Then stopped by a repair shop to have the emissions checked and they said the Evap was still reading as not ready. We purchased the car in Oct. and drive it regularly. We have not replaced the battery, the only thing we had was the teen safe module plugged in for the past 3 months. Will that module effect the computer readings?
Customer: replied 2 years ago.
There is no check engine light on, and never has been since we have owned this car.
Expert:  Skyvisions replied 2 years ago.

The module can affect it I would disconnect it. In the mean time let me look up the drive cycle.

Expert:  Skyvisions replied 2 years ago.

Is this a 4 cyl. or V-6 engine?

Customer: replied 2 years ago.
4 cly
Expert:  Skyvisions replied 2 years ago.

The drive cycle that the dealer gave you is not exactly correct. Even if you drove the drive cycle and the ambient temperature and the engine coolant temperature are not sufficiently separated on a cold soak start or overnight start the system will run the test correctly. Listed below is some of setting criteria to get the monitor test to pass. Bot***** *****ne is you just need to drive the pattern correctly. If it still will not pass there is a remote chance that could be an issue in the engine control computer. I would do this without the device plugged into the connector for the direct link. Also I've attached a graph showing the actual pattern that the computer is looking for it doesn't even require driving it simply a matter of the ignition off idling 3000 RPM rise and the allowing the engine to continue to idle. For the monitor or even have ready test it doesn't require driving. The other monitor test if they're not passing do have their own specific drive pattern. Hopefully this makes sense. Let me know how goes.



A cold soak must be performed prior to conducting the drive pattern to complete the internal pressure

readiness monitor.

(a) Cold Soak Preconditions

The monitor will not run unless:

_ The MIL is OFF.

_ Fuel level is approximately 1/2 to 3/4 full.

_ Altitude is 7,800 feet (2,400 m) or less.

(b) Cold Soak Procedure

Let vehicle cold soak for 8 hours or until the difference between IAT and ECT is less than 7°C (13°F).



_ Scenario 1

ECT = 24°C (75°F)

IAT = 16°C (60°F)

Difference between ECT and IAT is 8°C (15°F).

→ The monitor will not run because difference between ECT and IAT is greater than 7°C (13°F).

_ Scenario 2

ECT = 21°C (70°F)

IAT = 20°C (68°F)

Difference between ECT and IAT is 1°C (2°F).

→ The monitor will run because difference between ECT and IAT is less than 7°C (13°F).


IG SW off

Soak 15 to 50 minutes

(When the readiness code or diagnostic code

is set, this test is completed.)

3,000 rpm

10 seconds

Warm up time

(idle speed)