Posted on November 8, 2009 - by Richard

1999 Chevy Venture Scanner Won’t Work

Symptoms:

1999 Chevy Venture scanner won’t work when I scanned it 2 weeks ago. The engine ran good all the time and there’s no performance problem. The vehicle driver reported that sometimes, the power door locks would activate by themselves while driving.

Diagnostics for Chevy Venture won’t work:

I would start checking this 1999 Chevy Venture scanner won’t work problem by tracing the engine ground wires. This can be done by getting hold of the vehicle engine wiring diagram. From my experience, a major source of this scanner communication issue comes from corroded ground wiring connections to the ecm (engine computer) terminals. This can be tested by wiggling the engine compartment harness wires especially the ecm ground wires. Voltage measurement is done while the engine is running and measuring the ground voltage with ecm housing connected/disconnected and comparing the results. When measuring the ground voltage, it should read not higher than 0.250 volt where the positive lead of the voltmeter is connected to the ground wire. As always, the negative lead of the voltmeter is connected to the battery negative terminal of the vehicle. Remember to use a digital voltmeter when testing ground voltage reading to get accurate results.

Shown here is a Utube video I made for Chevy Venture won’t work:

Tip for 1999 Chevy Venture scanner won’t work:

With door locks activating by themselves, the BCM module should be disconnected and if the scanner communication is restored, the BCM module is defective. On some engine computer system, a shorted BCM module/wirings will disrupt the ecm operation. A quick pin voltage reading of the data bus terminal pins at the ecm terminal can also be used to test if the BCM is at fault. Normal voltage reading is about 2.5 volt when BCM is connected. If the latter is disconnected and the voltage reading became normal or 2.5 volt, the BCM module is confirmed defective. Please contact ATS for the exact BCM voltage specifications.

Note:

Whenever connecting or disconnecting BCM or ecm modules, always disconnect the battery negative terminal to prevent damage to the ecm and it’s components.

Thanks!