Great... Codes 0304 and 0504 :(
10-20-2005, 09:20 PM
#1
Great... Codes 0304 and 0504 :(
Hey guys, it's been a while since I've been to the .org, but I am in need of help once more. I've recently "aquired" the dreaded knock sensor code 0304, along with 0504, which is the "Automatic Transmission Control Unit Signal to ECU" code. I cleared the codes 2 days ago and sure enough, they both came back. I'm not too worried about the knock sensor, as there are tons of resources on how to change it and all that good stuff, but I am a bit concerned about the 0504 code. I read a post on here that said it might have something to do with the "drop resistor", but I'm not certain. Can anyone tell me what (specifically) I should check for? I've got this code in the past after some spirited driving on the freeway, but it went away on its own. Now it seems as if it's here to stay 
!
Thanks,
-Maurice
!Thanks,
-Maurice
10-20-2005, 09:24 PM
#2
do u have the drop resistor mod? if so, i dont remember if that is the code, but it will come on everytime u use the dr mod... i have a code related to the dr mod, i just leave it b/c i know it'll come bak wen i WOT
10-21-2005, 05:44 AM
#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 12mm 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.
0504
Diagnostic Trouble Code 0504 points to a problem with the Automatic Transmission Communications line. Pulse signals are exchanged between the Engine Control Module and the Transmission Control Module to assure smooth shifting during hard acceleration or deceleration.
This malfunction is detected when the ECM continuously receives an incorrect voltage from the TCM. Possible causes include...
- Harness or connectors (The communications line circuit between the ECM and the TCM is open or shorted.)
- TCM
- Discharged or faulty battery
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 12mm 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.
0504
Diagnostic Trouble Code 0504 points to a problem with the Automatic Transmission Communications line. Pulse signals are exchanged between the Engine Control Module and the Transmission Control Module to assure smooth shifting during hard acceleration or deceleration.
This malfunction is detected when the ECM continuously receives an incorrect voltage from the TCM. Possible causes include...
- Harness or connectors (The communications line circuit between the ECM and the TCM is open or shorted.)
- TCM
- Discharged or faulty battery
10-21-2005, 10:16 AM
#5
Not to be ungrateful, but I already read the stickies. They don't really help much as to how am I supposed to know exactly what's throwing the 0504 code and how serious it actually is.
10-21-2005, 03:06 PM
#6
I'm gonna shoot for a self-diagnosis here... Would it be feasible that bad coilpacks could possibly trigger this 0504 code? I've had bad coilpacks for a while now, but didn't think it would eventually lead to something else. Guess it's time to fork out $300 bucks or so..
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