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Discussion Starter · #1 ·
After reading several articles/postings regarding faulty ECU's and the symptoms associated (backfiring through exhaust & airfilter, stalling when pulling in clutch/brake). I decided to check my ECU in accordance with the Kawasaki Technical Manual as my 2007 VN900 Classic LT is experiencing the same symptoms. I know that there was a recall for 2006 ECU's. People reported that once the ECU was replaced, all the symptoms cleared up.
Here are the procedures:

•With the ECU connector joined, check the following
ground leads for continuity with the ignition switch ON or
OFF, using a digital voltmeter.

ECU Grounding Inspection
Meter Connections:
(Other than Europe Models)
26, 42, 43 (BK/Y) Terminal ←→ Battery (–) Terminal
22 (BR/BK) Terminal ←→ Battery (–) Terminal
Engine Ground ←→ Battery (–) Terminal

Readings: 0 Ω (regardless of the ignition switch ON or OFF)

Here were my readings:
26, 22, 42, 43 with ignition OFF: 0 ohms respectively
26, 22, 42, 43 with ignition ON: 0.3 ohms during 3 second fuel pump prime, after prime, readings are 0.15 ohms respectively.

Do these readings indicate a problem?
Can anyone who is saavy enough try this with their ECU and post back their readings?

Thank you, in advance, for your help.
 

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Crazy Old Guy
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A voltage drop test is more accurate and tests the circuits under load. You will need a digital voltmeter for this test. You should not have more than 50 milliamps (.050 amps) of drop between your negative battery post and your ground connection. I have a tool from Interstate batteries that lets me use a digital voltmeter instead of reading amps. The circuit goes through a resistor . . . blah, blah, blah.

What you need to know is if you are losing voltage anywhere except the relay or starter, etc.

You really shouldn't be checking ohms drop on a powered circuit, but that's just me talkin'.
 

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Discussion Starter · #3 ·
Thanks for the reply.

I'm just following what the manual is telling me to do?!?!?!?!?

The manual states: Readings: 0 Ω (regardless of the ignition switch ON or OFF)

But doesn't really say what to do if you DO find resistance. If there IS resistance, does this mean the ECU is bad or the grounding circuit on the bike?
 

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Discussion Starter · #4 ·
"A voltage drop test is more accurate and tests the circuits under load."

I have a digital multimeter. Do I start the bike and place one lead on the neg terminal and the other on the frame ground?
 

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Do not try and read resistance values on a live circuit. Good way to pop your meter.
Voltage drop tests are measured in volts, not amps.
Do the "key on" tests with your meter reading volts, not ohms and post back with your findings.
As a note, you are checking the ground return for your ECU, not the ECU itself.
 

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Crazy Old Guy
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"A voltage drop test is more accurate and tests the circuits under load."

I have a digital multimeter. Do I start the bike and place one lead on the neg terminal and the other on the frame ground?
Yes, if you have a 'min/max' function on your voltmeter, set it and just toggle through to see the max drop after you've started your bike.
 

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Crazy Old Guy
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Do not try and read resistance values on a live circuit. Good way to pop your meter.
Voltage drop tests are measured in volts, not amps.
Do the "key on" tests with your meter reading volts, not ohms and post back with your findings.
As a note, you are checking the ground return for your ECU, not the ECU itself.
Yep, you caught me! I stated amps and not volts. Sorry, I am usually testing for a parasitic load on the battery and that is where my amps slip up came through.
 

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Crazy Old Guy
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. . . But doesn't really say what to do if you DO find resistance. If there IS resistance, does this mean the ECU is bad or the grounding circuit on the bike?
If there is too much voltage drop (i.e. resistance) to your componant (i.e. starter), then there is usually a bad connection at one end of the wiring, or most common a loose connection, possibly a connector that has corrosion, etc.

ECU's have proven to be very durable and usually either work or they don't. I have specific automotive instances where that is NOT true, but for the most part they either work or don't. :mrgreen:
 

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Crazy Old Guy
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Thanks for the reply.

I'm just following what the manual is telling me to do?!?!?!?!?

The manual states: Readings: 0 Ω (regardless of the ignition switch ON or OFF) . . .
Usually in the manual, there is a small phrase that is often overlooked - disconnect the battery . . .

Most resistance tests are performed with the voltage source disconnected. The problem with this type of test is that the circuit is NOT loaded when checking.

The voltage drop test is a more accurate way of testing a loaded circuit. An example would be testing open circuit voltage of a battery, it may be 12.52 volts, but when loaded the battery fails the load test badly. This is a very simple scenario, but demonstrates the effectiveness of testing circuits under load, or 'working conditions'.
 

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Discussion Starter · #10 ·
Usually in the manual, there is a small phrase that is often overlooked - disconnect the battery . . QUOTE]

I have read the section thoroughly, and it does not say to disconnect the battery. I have attached the pages from the manual on the ECU....again...it never explains what to do if problems are found by running these checks?

The manual explains how to pull up codes by reading the FI light flashes and how to troubleshoot those codes based on the flash code. Based on the code, you run input/output voltage checks on the affected sensor and also resistance checks as well, if all checks out good, it says to replace the ECU. What if the ECU isn't pulling any codes, can it still be faulty? They recalled a bunch of 2006 ECU's but never said what was bad.
 

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I think that your best bet is to take the serial number of your bike to the dealer and see if it is included in the recall. If it is, then get it done. If it is not, post back with your symtoms and we can try and help.
 
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