GM TRANSFER CASE NOISES Customer complaints involving howling, whining, shudder or grinding noises during parking lot maneuvers in Auto Mode or highway speeds in 4HI or Auto may occur on four wheel drive GM trucks and SUV vehicles. Vehicles affected range from 2014–2023 year models. Specific applications can be identified in GM Service Bulletin 19-NA-136. […]
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A major part of the diagnostic process is identifying an issue from a normal characteristic. Following are some examples of customer complaints that could be mistaken as a problem when they may be a normal occurrence for the application. DIESEL ENGINES AND NOISE-RELATED SYMPTOMS Customer complaints of ticking, clicking, or cycling noises on 2017–2022 GM […]
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Customer complaints of rough idle, misfires, crank but no start or long crank time symptoms can be a challenge with today’s technology. Random or multiple misfire codes may be stored in memory. Symptoms that seem like an ignition related issue may actually be fuel related, carbon induced, or in some cases a normal characteristic. Fuel […]
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LOW FLUID LEVEL CAUSES POWER TRANSFER UNIT FAILURE Are you accurately checking those fluid levels and recommending fluid flushes or exchanges, where applicable? Unfortunately, many service technicians fall into a pattern of just performing lubrication services requested by the customer, which is usually triggered by a service reminder light indicating that it is time for […]
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Air filters are designed to protect the engine from contaminants such as bugs, dust, dirt and other debris. Engines do not perform well when the filters are subjected to water and snow, as these conditions promote a hydro-lock of the filter media. When the hydro-lock condition occurs, the filter can be pulled from the air […]
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New technology poses new challenges as smaller displacement turbocharged engines create some major challenges for the vehicle manufacturers and the technicians servicing the vehicles. When cruising, the turbocharged gasoline direct injected engines (TGDI) consume only a fraction of the fuel the larger displacement engines equipped with port fuel injection require. When called upon for performance, […]
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Turbocharged engines are becoming common, as vehicle manufacturers utilize smaller displacement engines. Turbochargers and direct injection can make a small displacement engine behave like a larger displacement engine, plus achieve better fuel economy, and that is the reason for their popularity. Engines that operate at higher altitudes benefit greatly from the turbocharged arrangement. Many fail […]
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When the customer complaint is poor or no acceleration or the engine has lost power, where would you start with the diagnosis? Most would assume something major and expensive to repair. Following are some basic checks to consider before getting too deep into the diagnostics. MAXIMA LOSES POWER A complete service had been performed and […]
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When most think of engine coolant (antifreeze) it is in relation to its freeze-point protection with little consideration of its ability to provide lubrication and protection from system corrosion. Unfortunately, engine coolant normally does not receive any attention until one of the following scenarios occurs: 1) The engine overheats. 2) Freezepoint protection for winter is […]
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On one vehicle the customer complaint started with a misfire condition which progressed to an extended crank time to start and eventually a no-start symptom. Performing the basic checks revealed…
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Create Engine Performance Challenges It was a busy morning with multiple vehicles arriving on roll-backs with no-start symptoms. The vehicles ran perfectly the previous day, only to encounter a no-start condition the following morning. The symptoms were that of loss of compression. Each vehicle…
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Timely vehicle maintenance makes good business sense, especially when compared to costly engine repairs or an engine replacement. The extended service intervals have created a major concern for the old school generation, and especially technicians that have serviced vehicles for thirty-plus years. Our early driving and maintenance experience encompassed less fuel…
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