The last 2 months or so my check engine light comes on and does not go off. It comes on after the car has been running for about 5 minutes every time you starts it up. I forced the codes out and I am getting 15 and 41. I looked up the codes and I know what they mean. I have already replaced the coolant sensor(15) and I have cecked the distributor (41) I have replaced the distributor cap, had the module tested and it was fine( the guy got it hot and it was still fine.) After doing each of these I disconnected the battery to clear the codes and they keep coming back. I have no clue what to do, all the wires are connected and not shorting out so I have no clue where to begin. Is there a service bulletin put out by GM for my 1984 Z??? I a,m wasting time and money and that has not been able to fix it like it has in the past.


Thanks for all help,
Drew

 

SX,

A continuous '15' likely means that you have an open circuit in to the CTS. Check the connector at the CTS, the grounds at the engine (near the rear end of the right head), and connections at the ECM. Your '41' could be a grounding problem as well, or a wiring problem between the distributor and ECM.

 

a popular misconception about DTC's is that it tells you the part you need to replace. It only tells you the system that is at fault. You need to get ahold of a GM service manual and follow the diagnostics to code 15 and code 41. In some cases, the fault may lie with something in another system giving the ECM a false value to determine others by. For instance, the code 33 problem commonly found in 85-87 TPI cars is actually the TPS's fault, not the MAF as the code says. Understanding DTC's is tricky and fixing them can be expensive if you don't have much experience.