I am a retired GM world class tech.
I replaced the tac motor connector after an engine overhaul and had no problems for six months. Then I got a p2135 and p1516. I diagnosed a bad throttle body tac motor and replaced it with a re-manufactured rockauto unit. Six months later same codes. so I warrantied the tac body. Six month later same codes. so I refreshed the PCM per a bulletin. Didn't fix it. So I replaced the throttle body with a new GM tac unit. Six months later only the p2135 came back with reduced engine power. I found another bulletin to replace the PCM if within the Julian build date but wondered if anybody has run into this. Once I had to rewire the tac throttle pedal pos. Sensor to the PCM as per GM tac engineer. Curious what anyone thinks. Haven't replaced PCM yet or even checked the Julian date because I don't think that's it.
I replaced the tac motor connector after an engine overhaul and had no problems for six months. Then I got a p2135 and p1516. I diagnosed a bad throttle body tac motor and replaced it with a re-manufactured rockauto unit. Six months later same codes. so I warrantied the tac body. Six month later same codes. so I refreshed the PCM per a bulletin. Didn't fix it. So I replaced the throttle body with a new GM tac unit. Six months later only the p2135 came back with reduced engine power. I found another bulletin to replace the PCM if within the Julian build date but wondered if anybody has run into this. Once I had to rewire the tac throttle pedal pos. Sensor to the PCM as per GM tac engineer. Curious what anyone thinks. Haven't replaced PCM yet or even checked the Julian date because I don't think that's it.
Jun 23, 2019 at 6:28 PM
