Automotive Service Technician (AST)

2012 Guide - Second Period Package (36 Modules) Comments

Date: 1/19/2026 12:17:28 PM
Module: 090201c
Version: 1st Edition
Page: 65
Comment: Figure 67 shows a special micrometer for measuring valve stem height. - - - in fact it is not a special micrometer - - The figure caption has it correct stating - - - Figure 67 - Measuring valve stem height with a caliper. - - (and it does actually show a "Caliper")
Status: Approved for Review

Date: 1/29/2026 3:32:03 PM
Module: 090201c
Version: 1st Edition
Page: 5
Comment: ILM - - Pre-Combustion Chamber (Diesel) A pre-combustion chamber is a separate chamber located in some diesel cylinder heads. This chamber conditions the fuel for final combustion in the cylinder, as depicted in Figure 4. The chamber may be integral with the head casting or removable as a separate component. ------ The wording "conditions the fuel" ------ This wording seems off - conditioning the fuel to me seems more like a chemical conditioner (common additives) Better wording ?? A pre-combustion chamber is a separate chamber located in some diesel cylinder heads. This chamber provides a hot, turbulent region where injected fuel begins to mix with air and ignite, then directs the burning gases into the main cylinder for complete combustion, as depicted in Figure 4.
Status: Approved for Review

Date: 2/2/2026 10:51:50 AM
Module: 090201dB
Version: 1st Edition
Page: 25, 63, 69
Comment: Module states on page 25 " Roller lifters should only be reused if they are in acceptable condition and mated with the camshaft lobes that they were in contact with before disassembly. Install new roller lifters or follower assemblies with a new camshaft." --------------------------------Self Test ----------------- Question 11 Roller lifters must be replaced as a set when the camshaft is replaced. a) True b) False -------------------------------Answer Key---------------------------- 11. b) False; roller lifters do not need to be replaced if the camshaft is replaced. ------------------------------------------------------------------ Module states replace - self test seems to disagree -
Status: Update in Progress

Date: 1/23/2026 8:45:18 AM
Module: 090201f
Version: 1st Edition
Page: 1
Comment: Module states - - - - Importantly, this module addresses safety, covering proper ventilation and the precautions you should take while working with running vehicles inside a shop environment. ------------------------------------------------------- Trouble is - you removed the section about GAS VENTING - PAGE 22-23 in old ILM - ---------------------------------------------------- Think you should put that section back or at the very least also remove the statement on page 1
Status: Approved for Review

Date: 1/23/2026 12:44:27 PM
Module: 090201h
Version: 1st Edition
Page: 36
Comment: Hose storage? Was not in previous ILM - - - - Why now? As someone that has been in the trade for 50 years I cannot understand why this is included - Seems more fitting for a Red Seal PARTS person... I have been a tech, foremen, service manager, parts manager and Fixed ops manager - I would suggest this got mixed up from the PARTS Modules???
Status: Approved for Review

Date: 10/30/2025 6:10:29 PM
Module: 090201i
Version: 2025
Page: 847,863,891
Comment: The text states that the major thrust side of the piston is the side contacting the cylinder wall on the power stroke, but the answer key for Activity One, Question Three, the answer key states it is the side of the piston contacting the cylinder wall on the compression stroke.
Status: Approved for Review

Date: 2/23/2026 12:20:27 PM
Module: 090202a
Version: 1st Edition
Page: 1
Comment: Module states that Objectives 10, 11, 12, 13, 14, and 15 are practical objectives and are not covered in this module. Please review adding this information back.
Status: Approved for Review

Date: 2/23/2026 12:12:27 PM
Module: 090202b
Version: 1st Edition
Page:
Comment: Review the removal of Objective 4 along with many pages from Objective 3 material. The module states "Objective four is a practical objective and is not covered in this module" on page 1, why? Old ILM have pages 25 to 31. This information is still pertinent and should be included. Yes, clutches are becoming still something we work on - and will for years to come.
Status: Approved for Review

Date: 2/6/2026 1:59:01 PM
Module: 090203a
Version: 1st Edition
Page: 35
Comment: ILM states----- Motorized Actuator Quick Check Procedure Motorized axle actuators, like that in Figure 28, can be tested by using jumper wires as described below. Follow the steps below in the event of a manual transfer case. 1. Apply 12-volt battery voltage to Terminal C and ground to Terminal E of the actuator. 2. Apply B+ on Terminal D; the plunger should immediately extend. 3. Remove B+ from Terminal D; the plunger should immediately retract. Follow the steps below in the event of an electronic transfer case. 1. Apply 12-volt battery voltage to Terminal C and ground to Terminal E of the actuator. 2. Apply ground on Terminal B; the plunger should immediately extend. 3. Remove ground from Terminal B; the plunger should immediately retract. ----------------------- The picture this refers to is on page 36 This picture works for the first section of a manual transfer case However It does not work for the automatic transfer case The instructions refer to Terminal B (there is no B) Think you need to add or at least refer to the right picture (Figure 25 on page 27)
Status: Approved for Review

Date: 1/22/2026 1:58:15 PM
Module: 090204bA
Version: 1st Edition
Page: 5
Comment: Module states: Plate clutch-type traction-enhancing differentials are an earlier version of the traction-enhancing technologies. This style works very similar to an automatic transmission clutch pack. Module shows a picture of internal transmission clutch pack. In the old ILM 090204c on Page 12 there is a proper picture of a diff clutch pack. Replace with a proper image.
Status: Approved for Review

Date: 9/22/2025 2:38:19 PM
Module: 090204bB
Version: 2025 edition
Page: 21 and The Final Self Test
Comment: The picture on page 21 is of an axle seal NOT a pinion seal, The Self Test has question 2 as AABC as opposed to ABCD
Status: Approved for Review

Date: 2/3/2026 1:32:40 PM
Module: 090205c
Version: 1st Edition
Page: even
Comment: Small formatting error - All ODD pages have numbers - all EVEN pages the page numbers are missing
Status: Update in Progress


Archived Comments

Year: 2021

6/22/2021 11:46:42 AM
Module: 090201o
Version:
Page:
Comment: The calculation of the increase in boiling point of coolant due to an increase in pressure has some errors. The ILM states that 3.25F is 2C. This is not correct -one degree Celsius is 1.8 times larger than one degree Fahrenheit. This error shows up in the calculation as the final answer calculted in fahrenheit is 257.5F. 257.5F is actually 125.3C not 128C as is calculated using metric. Using 2C is equal to 3.6F, you calculate 212F + (14 *3.6F) = 262.4F. 262.4F is equal to 128C. Also the starting point for the calculation is given at 212F (100C) (the boiling point of water) not sure why that is used rather than 225F (107C) given for a 50/50 mix on pg 7. The calculation is the for the boiling point elevation of coolant, not water.
Status: Implemented

6/22/2021 11:11:06 AM
Module: 090202b
Version:
Page: 1
Comment: Objective one for manual TRANSMISSIONS states "Describe the purpose, operation and construction of a manual TRANSAXLE and and its components."
Status: Implemented

6/22/2021 11:05:52 AM
Module: 090201g
Version:
Page: 26
Comment: It states that a cam follower is a second class lever because the fulcrum is at the end rather than the middle. However the placement of the effort (cam) and load (valve spring) are not considered. A second class lever has the load in the middle and the effort at the end opposite the fulcrum. This gives allows a smaller effort force moving over a large distance to move a heavy load a small distance (like a wheelbarrow). In the case of the cam follower, the fulcum is an one end, the effort (action of the cam) is in the middle and the load (valve spring to be compressed) is at the other end. This makes the cam follower a third class lever. In a third class lever, the load travels farther than the effort which correlates to valve lift being greater than cam lift (rocker ratio).
Status: Implemented

6/22/2021 10:32:25 AM
Module: 090201m
Version:
Page: 14
Comment: The paragraph that begins with "Inspect all exhaust system heat shields..." below figure 16 is identical to the paragraph higher up on the page (one paragraph above figure 16)
Status: Implemented

5/13/2021 9:49:17 AM
Module: 090204c
Version:
Page:
Comment: Self-Test Question 6 asks which gears are used on remote final drive assemblies; this topic is not covered in the module.
Status: Declined

Year: 2020

4/17/2020 10:38:55 AM
Module: 090205c
Version:
Page:
Comment: I have had student come out of the AIT exam totally confused asking me "what is multiplexing?" as there is a question on the exam about multiplexing. There is currently no mention of multiplexing in the 1st or 2nd period modules. It was in the older 2nd period material. I believe that we need to add a paragraph or two as an overview of multiplexing to this module.
Status: Declined

1/6/2020 9:35:05 AM
Module: 090202a
Version: 21
Page: 31
Comment: Figure 34 is missing
Status: Implemented

Year: 2019

12/5/2019 1:25:57 PM
Module: 090201e
Version: 21
Page: 38
Comment: Answers for question #3 are incorrect. The picture was changed in the last revision, but the answers were not changed to match the new picture.
Status: Implemented

12/5/2019 1:23:13 PM
Module: 090201i
Version: 21
Page: 17
Comment: Figure 17 is incorrect. The picture is NOT an impeller wheel. (It is a differential drive pinion)
Status: Implemented

12/2/2019 8:45:56 AM
Module: 090201d
Version: 21
Page: 23
Comment: Answer to question #5 is incorrect. It states that bearings matched to the crankshaft should be oversized. This is incorrect. The bearings needed are undersized due to the inside diameter. The bearings now form a smaller diameter which makes them undersized. The bearing manufactures will identify this on the back of the bearing with a mark like this - 0.010us. The correct answer should be A
Status: Implemented