ECU Codes

[kwas911]

I just bought a 97 Maxima SE with 61k miles. I have driven it only 60 miles and the "service engine soon" light came on. I checked the codes and got: 07-05 (EVAP Control System), 07-07 (Rear Heated o2), 09-03 (EVAP Canister Vent Control Valve). Is it normal for these three to happen all at once? Does that light ever come on in error? Do I need to get these parts replaced immediately? Thanks

[97GLEMAX]

I am not sure what they all mean but I do know I replaced the canister and it wasn't expensive. Just bring it to someone that works on Nissan and ask them anout the other two things but the canister can what a little.

[kwas911]

I clear the ECU codes and the light came back on after a few days. I checked it again and got the same 3 codes (0707-Rear Heated O2 sensor, 0705-EVAP Control Syste, 0903-EVAP Canister Vent Control System). Can anyone tell me how these parts cost and whether I can replace them myself. Thanks in advance.

[97wvmax]

i dont remember how much the parts were, but if u look thru the first page or 2 of the max forum there is another thread about all of this

[Ravq]

Diagnostic Trouble Code 0705 points to a problem with the Evaporative Emission Control System.

This malfunction is detected when the EVAP control system has a leak or the EVAP control system does not
operate properly. (EVAP = EVAPorative emissions.) Possible causes include...

- incorrect fuel tank vacuum relief valve
- incorrect fuel filler cap
- fuel filler cap vent remains open or fails to close
- foreign matter caught in fuel filler cap
- a leak in the line between the intake manifold and the EVAP Canister Vacuum Control Valve
- foreign matter caught in the EVAP CVCV
- leaks in the EVAP canister or fuel tank
- leaks in the EVAP purge line (pipe and rubber tube)
- EVAP purge line rubber tube bent
- blocked or bent rubber tube to EVAP control system pressure sensor
- loose or disconnected rubber tube
- EVAP CVCV and circuit
- EVAP Canister Purge Volume Control Solenoid Valve and circuit
- absolute pressure sensor
- tank fuel temperature sensor
- MAP/BARO switch solenoid valve and circuit
- blocked or bent rubber tube to MAP/BARO switch solenoid valve
- O-ring of EVAP CVCV is missing or damaged
- water separator
- EVAP canister saturated with water
- EVAP control system pressure sensor
- refueling EVAP vapor cut valve
- ORVR system leaks

This is a "jackpot" code. It points to so many possible causes as to be almost useless. It may be accompanied by another DTC which is more specific.

[Ravq]

DTC 0707 is detected when the Engine Control Module determines that the response time of the Rear Heated Oxygen Sensor is excessive. The possible causes include ...
- Harness or connectors (the sensor circuit is open or shorted.)
- Rear Heated Oxygen Sensor
- Fuel pressure
- Fuel injectors
- Intake air leaks

[Ravq]

Diagnostic Trouble Code 0903 points to a problem with the EVAP Canister Vent Control Valve.
EVAP = EVAPorative emissions control system. This is the system which seeks to minimize air pollution which results from evaporation (as opposed to incomplete combustion) of gasoline.

The EVAP CVCV is located on the EVAP canister (underneath the vehicle near the left rear tire) and is used to
seal the canister vent. It has one hose connection and one two-wire electrical connector. The solenoid in the
EVAP CVCV responds to signals from the ECM. When the ECM sends an ON signal, the coil in the solenoid valve is
energized. A plunger then moves to seal the canister vent. The ability to seal the vent is a necessary part of
the diagnosis algorithms for other evaporative loss system components. This solenoid valve is used only for
diagnosis, and usually remains open. When the vent is closed, under normal purge conditions, the evaporative
loss system is depressurized allowing "EVAP Control System (Small Leak)" diagnosis. Since this part is used only
for brief emissions tests the vehicle will usually start and run well despite a Service Engine Soon warning light on
the dashboard.

The EVAP CVCV may be bench tested. Remove it from the vehicle (one hose, one connector, two bolts). Verify
that air may pass freely through the valve. Then use a pair of fused test leads to apply 12 volts to the terminals
to energize the solenoid. Verify that air does not pass freely through the valve. If the CVCV fails these tests, try
cleaning it with WD-40 and compressed air. If this fails to free it up, replace the valve. When you install a CVCV
(the original or a replacement) always use a new O-ring.