Advice On My ECU codes.
02-02-2004, 03:01 PM
#1
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Thread Starter
Join Date: Oct 2003
Posts: 18
Advice On My ECU codes.
My check engine light came on last night, and I just went out and checked the codes:
0304 - "Knock Sensor"
0303 - "Front Left Heated O2 sensor"
I just changed that sensor 2 months ago. Is their a chance that I need to replace it again?
That being said I read the descriptions on both... Is it possible my Knock Sensor tripped the O2 Sensor?
Should I replace the Knock Sensor?
Other Info:
Has 87,000 Miles
I Run 91 Octane
O2 Sensor was replaced about 4,000 miles ago. It's a Bosch.
Please Help!
-Matt
0304 - "Knock Sensor"
0303 - "Front Left Heated O2 sensor"
I just changed that sensor 2 months ago. Is their a chance that I need to replace it again?
That being said I read the descriptions on both... Is it possible my Knock Sensor tripped the O2 Sensor?
Should I replace the Knock Sensor?
Other Info:
Has 87,000 Miles
I Run 91 Octane
O2 Sensor was replaced about 4,000 miles ago. It's a Bosch.
Please Help!
-Matt
02-03-2004, 03:00 PM
#4
0304
Diagnostic Trouble Code 0304 points to a problem with the Knock Sensor. The KS is attached to the cylinder block. It senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is senses as vibrational pressure. This pressure is converted into a voltage signal and sent to the Engine Control Module (The computer).
This malfunction is detected when an excessively high or low voltage from the KS is entered to the ECM. Possible causes include...
- the harness or connector (The KS circuit is open or shorted).
- the KS
The KS may be checked with an ohmmeter.
1) Raise the hood. View the engine from the driver's fender. Look into
the deep valley between the cylinder banks and below the intake manifold.
Identify the KS as a black item fastened to the block by a single vertical
bolt. A wire harness wrapped in black leads toward you, out of the valley.
That is the KS sub-harness.
2) Follow the KS sub-harness to it's nearest connector. This is connector F121.
It is located near the upper right-hand corner of the valve cover of the forward cylinder bank, as viewed from the front of the car.
3) Disconnect F121. You have to do a "press the latch and wiggle and
pull" to disconnect it. F121 has only two pins; if you see more than two
pins, you have the wrong connector. Use a digital ohmmeter capable of
measuring more than 10 Megohms. You want to measure the pins of F121, not
the sockets of the matching connector. Measure the resistance between a
good ground (such as the battery negative terminal) and pin #2 of connector
F121. On my car this is the highest of the two pins, the one closest to
the front of the car. The factory spec is 500 - 620 Kohms.
The manual says you have to remove the intake manifold to replace the KS. However, I think that a person with good dexterity and a 10mm ratcheting box wrench could replace the KS without disturbing the manifold.
Important note: the dealer can do a more thorough test with his CONSULT electronic tester. The resistance test described here is a useful but limited test. A Knock Sensor which fails this test is definitely bad. However, a KS which passes this test is not guaranteed to be good.
Read FAQ's and Howto's
0303
Diagnostic Trouble Code 0303 indicates a problem with the front Oxygen Sensor on the left cylinder bank. The left bank is also called the front bank. It is cylinders 2,4,6. A normal signal sweeps back and forth between 0.2 volts and 0.8 volts. This malfunction was detected when the Engine Control Module received a signal from the sensor which was a constant value of approximately 0.3 volts.
Possible causes include ...
- Harness or connectors (the sensor circuit is open or shorted).
- Defective Oxygen Sensor
www.buyoxygensensors.com
Diagnostic Trouble Code 0304 points to a problem with the Knock Sensor. The KS is attached to the cylinder block. It senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is senses as vibrational pressure. This pressure is converted into a voltage signal and sent to the Engine Control Module (The computer).
This malfunction is detected when an excessively high or low voltage from the KS is entered to the ECM. Possible causes include...
- the harness or connector (The KS circuit is open or shorted).
- the KS
The KS may be checked with an ohmmeter.
1) Raise the hood. View the engine from the driver's fender. Look into
the deep valley between the cylinder banks and below the intake manifold.
Identify the KS as a black item fastened to the block by a single vertical
bolt. A wire harness wrapped in black leads toward you, out of the valley.
That is the KS sub-harness.
2) Follow the KS sub-harness to it's nearest connector. This is connector F121.
It is located near the upper right-hand corner of the valve cover of the forward cylinder bank, as viewed from the front of the car.
3) Disconnect F121. You have to do a "press the latch and wiggle and
pull" to disconnect it. F121 has only two pins; if you see more than two
pins, you have the wrong connector. Use a digital ohmmeter capable of
measuring more than 10 Megohms. You want to measure the pins of F121, not
the sockets of the matching connector. Measure the resistance between a
good ground (such as the battery negative terminal) and pin #2 of connector
F121. On my car this is the highest of the two pins, the one closest to
the front of the car. The factory spec is 500 - 620 Kohms.
The manual says you have to remove the intake manifold to replace the KS. However, I think that a person with good dexterity and a 10mm ratcheting box wrench could replace the KS without disturbing the manifold.
Important note: the dealer can do a more thorough test with his CONSULT electronic tester. The resistance test described here is a useful but limited test. A Knock Sensor which fails this test is definitely bad. However, a KS which passes this test is not guaranteed to be good.
Read FAQ's and Howto's
0303
Diagnostic Trouble Code 0303 indicates a problem with the front Oxygen Sensor on the left cylinder bank. The left bank is also called the front bank. It is cylinders 2,4,6. A normal signal sweeps back and forth between 0.2 volts and 0.8 volts. This malfunction was detected when the Engine Control Module received a signal from the sensor which was a constant value of approximately 0.3 volts.
Possible causes include ...
- Harness or connectors (the sensor circuit is open or shorted).
- Defective Oxygen Sensor
www.buyoxygensensors.com
02-03-2004, 04:10 PM
#6
funny, i got that code today, 0304, 0503, and 0307. i'm gonna reset it and hope it goes away. good and bad to see the cel, i thought maybe it didn't work anymore since i haven't had one in forever and my car was being weird before. funny that now when i seemed to have fixed all the problems and it's running great, i get a cel!
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