Professional automotive forum for discussion of the theory of operation for any automotive system or component. Discussions include electrical and electronic theory, engine propulsion theory, fuel system theory, ignition systems theory, and much more. This forum is for experienced automotive repair professionals only, membership required.
Continue to the description of our next automotive discussion forum, the Technical Tips Forum.
| Stepper Motors 08/23/2025 in the Technical Theory Forum Servo motors, 3-phase BLDC motors and stepper motors are increasingly common on modern cars. They are even more common on EV's. And they are widely misunderstood (IMO). Stepper motors are especially unique and confusing. I first encountered stepper motors... | ||
| Ground isolation on hybrid vehicles HV wiring 08/22/2025 in the Technical Theory Forum I was doing a ridiculous amount of testing on the electronics of several 2010-2014 Toyota hybrid a/c compressor systems. A big surprise I got, was to find that the compressor case is grounded by the HV ground wire. With a loose compressor plugged into the... | ||
| Flashing Ambient Temperature Indicator 08/20/2025 in the Technical Theory Forum [Miscellaneous: 18 Hyundai Elantra Value Edition 2.0L] The ambient temperature indicator in the instrument cluster has 3 flashing dashes with the F for fahrenheit symbol. The only service information I can find is how the ambient sensor works. I am confi... | ||
| Dual thermostats. Purpose and diagnostics 06/28/2025 in the Technical Theory Forum We have been seeing some cars with dual thermostats. I have not yet understood their purpose. Even worse, how to diagnose them. If I find a circulation problem I replace both thermostats. Can you help me understand the design, and any tips on determining ... | ||
| PCM pid data chart 06/03/2025 in the Technical Theory Forum [Driveability: 21 Jeep Cherokee Limited 3.2L] Can not ID correct vehicle here. Is actually Grand Chero w/ 3.6L. I suspect I have a defective fuel tank pressure sensor but have no baseline info on Mitchell (ShopKey) about what FTPS pid should read koeo an... |
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