Hi. My 1994 Suburban with a 6.5 turbo diesel threw a 29 code which appears to be related to the glow plug system. My glow plugs are Bosch replaced about 8 years ago, with a new GP controller. The vehicle has 235,000 miles on it, has a relocated PMD, and a high capacity Powermaster alternator. Other than that pretty much a stock engine. It has been pretty reliable. I'm wondering if my GP cables might be the culprit and am looking to hear what other people have had to fix with a 29 code.