Hey all. I was just wondering if I can use a timing light to fix the P1345 code? I see that it’s very easy to adjust the CMP retard with a decent scanner but I don’t have one. I was wondering if I could use a timing light to adjust the timing to resolve this code? Both methods require you to turn the distributor. Is CMP retard the same as timing? If I use a timing light to adjust my distributor so that I’m between +- 2 degrees of TDC, is this the same thing as using a scanner to set CMP retard to +- 2 degrees.
Let's start with providing some basic info regarding what you're working on. Year, make, model, engine, transmission. Given you're asking about CMP retard, I'm guessing 1996 later vortec engine.
CMP adjustment is different than the traditional timing setting. Yes, they both require turning the distributor but CMP is the correlation of the cam sensor with the crank sensor. I think the ignition timing on the vortecs is controlled fully electronically (if I'm off here, i trust others will chime in and correct me)
CMP retard adjustment
REQUIRES a scan tool of some sort to adjust it to within spec. Some on here have had luck with bluetooth OBD2 adapters and an app (I have no experience here). Dashcommand with the appropriate in app extension for additional PIDs, if memory serves me well. Do a sesrch on the forum for CMP. Others opt for the used professional scan tool route via ebay or elsewhere. Of course, you could always take it to a shop you trust, pay an hour of labor and have them set it.