Ch12i5

02 01

03 04

I've been getting these occasionally, and they've always been these two. Usually, the check engine light comes on when i drive the car a little hard (4000rpm+, but not over 5200rpm)

does anyone have a solution to what could be wrong? am i going to have to take it to the dealer...again?

phatmax95

iTrader: (29)

you can go here to read the codes.. http://vbxmaxima.8m.com/ecudecoder.html .. those 2 mean Ignition Signal Circuit .. and Knock Sensor .. what kind of gas are you using.. mayeb with the high revving the gas pings, or something.. im not too sure...just my input

Daniel B. Martin

Diagnostic Trouble Code 0201 indicates a problem with the ignition coil and power transistor. The ignition signal from the Engine Control Module is sent to and amplified by the power transistor. The power transistor turns on and off the ignition coil primary circuit. This on-off operation induces the proper high voltage in the coil secondary circuit.

The malfunction is detected when the ignition signal in the primary circuit is not entered during engine cranking or running.

The items to check include
- Harness or connectors (the ignition primary circuit is open or shorted.)
- Power transistor unit built into ignition coil
- Condenser
- Crankshaft Position Sensor (REF)
- Crankshaft Position Sensor (REF) circuit

I would have expected to see DTC 0201 along with other DTCs. Were there any others? A misfire on any individual cylinder should set a code, and a problem with the CPS should also set a code.

You may get one or more of the following DTCs:
0407 - Crankshaft Position Sensor (REF)
0608 - Cylinder 1 misfire
0607 - Cylinder 2 misfire
0606 - Cylinder 3 misfire
0605 - Cylinder 4 misfire
0604 - Cylinder 5 misfire
0603 - Cylinder 6 misfire

Daniel B. Martin

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 passes this test is not guaranteed to be good. However, a Knock Sensor which fails this test is definitely bad.

Daniel B. Martin

Diagnostic Trouble Code 0201 is the more important of the two Codes. Please focus your efforts on resolving that problem. There's a chance that fixing the DTC 0201 problem will get rid of both codes.

Ch12i5

just wanted to say thanks Daniel, for all of the info. it's very helpful that i have this thread to look back on for reference.