Need Cam crank waveform for 2002 Buick with 3.4
Looking for cam crank wave form. Looking for what the voltage high and low on the cam sensor is supposed to be. Looking at the scan tool while cranking it said I had all the crank sensor signals but said no on the cam sensor PID. Hooked up a scope to cam sensor at the harness and at the Pcm and had a 9.5 volt high and .125 volt ground. The voltage was 10 with the battery charger connected. Is it supposed to be 12 volts?
03 Impala 3.4 cmp ckp at idle. Minimum battery cranking voltage is 9.8 volts.
No cam signal will usually only cause long crank as pcm guesses which injector to start firing, not a no start. What are you missing- spark, pulse?
No injector pulse and 2 different scanners said no cam signal on data pids. Scoped power, ground, and signal wire on cam sensor at pcm and sensor with the signal being lower than input voltage. Curious what the threshold voltage is for signal.
The Cam sensor voltage while cranking should be near 10-11 volts.
04 Blazer 4.3 cmp ckp voltages cranking to start with a weak battery. HTH
On the 03 Impala 3.4, look at the bottom of the page for the “Channel Labels”
Do you have power going to injectors-not trying to insult- just trying to think of anything else. I think if you have that signal voltage toggling at PCM connector and PCM reports no cam signal, I would consider pcm is at fault. Used ones are cheap- no programming, but you will have to learn theft as that's what it prevents- injectors from pulsing.
No insult taken, yes we have power to and through the injectors, but no control. No codes in any modules at this point.
Pcm would be my guess and I as stated earlier, a used on could be had for fifty bucks, but the only question would be if you got a good one. Highly unlikely you would get one with the same issue however and then at least you would know and maybe fit it for a remanned once confirmed.
Should be able to do a scratch test on one this old: use an old-fashioned testlight to b= and tap into the PPL/Wht wire at the ICM. Tap the wire with the key on, the injectors should fire…that will tell you whether the PCM has an issue. And, as others have said, it should still run even with a failed cam sensor. Even the Tech 2 will often show no CAM signal present (depending on Y/M/M) many…
Thanks, I'm waiting for the shop to bring it to me so I can start from scratch. I have a diagnostic routine that I like to follow and I get distracted easily when they are looking over my shoulder trying to help,lol. I've tried to work on it outdoors at their shop but I can't see as well as I used to so I really like to have my 48" screen to help me see whats going on.
Started at the beginning. Backprobed injector control, Current probe around all injector B+, CMP, CKP at the pcm. Had no 24x ckp signal. Checked for signal at the sensor and had a signal. Ran a jumper wire from ckp sensor to pcm and it started. Shop was confused because it had spark, that comes from a different ckp sensor.