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Auto IQ 15-Stage Diagnostic Process
Workshop SOP  ·  Mandatory on every diagnostic job  ·  Three stages, three customer authorisation points
Purpose

The Auto IQ 15-Stage Technical Evaluation Process is the diagnostic framework used on every diagnostic job at Fergies. It is a structured, methodical approach to fault finding that ensures no steps are skipped, every conclusion is evidence-based, and every output is documented clearly enough for front of house to present the findings and their value to the customer and obtain authorisation to proceed.

This SOP exists to ensure every diagnostic job is carried out consistently and to the same standard by every Troubleshooter Technician. It protects the customer by ensuring faults are found correctly first time, protects the technician by making every diagnostic conclusion evidenced and defensible, and protects the business by giving front of house the information they need to sell each stage of the process confidently.

The three-stage structure
Stage 1 — Technical Evaluation
Steps 1 to 7
1 hour total
45 mins evaluation plus 15 mins Garage Hive write-up. Output is the test plan and implications for FOH to sell Stage 2.
Stage 2 — Diagnostic Confirmation
Steps 8 and 9
Quoted and authorised
Carry out the tests and confirm root cause. Output is the Stage 2 write-up for FOH to sell Stage 3.
Stage 3 — Repair
Steps 10 to 15
Quoted and authorised
The repair, post-fix operations, confirmation, documentation and CPD. Output is the completed job card.
The three customer authorisation points
Stage 1 completeFOH sells Stage 2 diagnostic time
Stage 2 completeFOH sells Stage 3 repair
Stage 3 completeFOH calls customer for collection
Who this SOP applies to
  • All Troubleshooter Technicians — Junior, Mid and Senior
  • The Workshop Manager when carrying out or supervising diagnostic work
  • Junior Troubleshooter Technicians follow this SOP under WSM supervision until assessed as competent to carry out Stage 1 independently
When this SOP applies
  • Every diagnostic job, every time — regardless of how familiar the fault appears
  • Familiarity with a fault type is not a reason to skip steps in the process
  • Both Stage 1 and Stage 2 require a written Garage Hive output before the next stage can begin
  • No stage begins without the previous stage write-up being complete and customer authorisation confirmed on the job card
Customer communication

No diagnostic findings, repair recommendations or costs are ever communicated directly to the customer by the technician. All customer communication goes through front of house at every stage.

Health and safety considerations

Diagnostic work involves working with vehicles, electrical systems, diagnostic equipment and in some cases chemical exposure. The following health and safety considerations apply.

Electrical systems

When working with or near high-voltage systems on hybrid or electric vehicles, manufacturer-specific isolation and safety procedures must be followed before any diagnostic work begins. Refer to the manufacturer workshop manual for the specific vehicle. Do not begin diagnostic work on a high-voltage system without completing the required isolation procedure.

Road test safety

The road test during Stage 1 must only be carried out by a qualified driver holding a full UK driving licence valid for the category of vehicle being tested. All road traffic law applies. The technician must be familiar with the vehicle controls before moving off.

Ramp safety

Where diagnostic work requires the vehicle to be raised on the ramp, the vehicle must be correctly positioned, secured and the ramp locks engaged before any work beneath it begins. Follow the workshop ramp operating procedure at all times.

Fluid and chemical handling

If diagnostic work involves handling brake fluid, coolant or other hazardous substances, refer to the workshop COSHH register for full handling and disposal requirements. Nitrile gloves must be worn when handling brake fluid. Eye protection must be worn when working beneath the vehicle.

Diagnostic equipment

Manufacturer genuine diagnostic tools must be used at all times. Ensure the diagnostic tool is fully updated before connecting to any vehicle. Never force a diagnostic connection or attempt to connect to a system the tool is not rated for.

Equipment and materials required

All diagnostic equipment must be checked at the start of every working day and confirmed in full working order and fully updated before any diagnostic job begins. Report any faulty or out-of-date equipment to the Workshop Manager immediately.

Manufacturer diagnostic tool
Genuine manufacturer diagnostic equipment — fully updated and appropriate for the vehicle make
Garage Hive
Job card open and accessible — both Stage 1 and Stage 2 write-up templates ready
Technical resources
Access to manufacturer technical information, TSB database and TPI library
Multimeter
Calibrated multimeter for circuit testing in Stage 2
Oscilloscope
Where available and required for signal testing in Stage 2
Workshop timing device
To monitor the 45-minute Stage 1 evaluation window
Stage 1 — Technical Evaluation (Steps 1 to 7)

The full Stage 1 allocation is one hour — 45 minutes for the technical evaluation and 15 minutes for the Garage Hive write-up. These two windows are separate and protected. If 45 minutes is not sufficient, additional time must be requested from the Workshop Manager before the evaluation window expires.

45 minutesTechnical evaluation — steps 1 to 7
15 minutesGarage Hive write-up
At 45 minutes — stop and request more time if needed

If the technical evaluation is not complete at 45 minutes, the technician stops and requests additional time from the Workshop Manager before proceeding. The 15-minute write-up window is protected — it must never be sacrificed to extend evaluation time.

Step 1
Customer Contact
Confirm the customer concern in full before touching the vehicle — what, when, under what conditions, how long.
Step 2
Confirm Fault
Attempt to replicate the reported fault under the conditions described by the customer. Document the result.
Step 3
Fault Codes
Full system scan across every module. If multiple codes, delete and road test to identify which return.
Step 4
Serial Data
Review live and recorded serial data relevant to the fault and stored codes.
Step 5
Research
Check TSBs, manufacturer technical information and TPIs. Attach any relevant TPI to the job sheet.
Step 6
Visual Inspection
Thorough visual inspection of the relevant system — wiring, connectors, components, fluid levels.
Step 7
Form a Plan
Form a specific, structured test plan for Stage 2 using all data gathered. This is the Stage 1 written output.
Stage 2 — Diagnostic Confirmation (Steps 8 and 9)

Stage 2 begins only once the Stage 1 write-up is complete and front of house has confirmed customer authorisation on the job card.

Stage 2 never begins without customer authorisation

The technician waits for front of house to update the job card before starting Stage 2. They do not begin because they believe the customer will say yes.

Step 8
Carry Out Tests
Execute every test in the Stage 1 plan in order. Document the result of each test as it is completed. Do not skip steps.
Step 9
Confirm Conclusion
Confirm root cause based on test results. The conclusion must be supported by evidence — never assumed. This is the Stage 2 written output.
Stage 3 — Repair (Steps 10 to 15)

Stage 3 begins only once front of house has presented the Stage 2 confirmed diagnosis to the customer, agreed the repair cost and obtained authorisation on the job card.

Stage 3 never begins without customer authorisation

The technician does not begin the repair until front of house has updated the job card to confirm the customer has authorised the work and agreed the cost. No exceptions.

Step 10
Call Customer
Front of house contacts the customer. The technician ensures the Stage 2 write-up is complete enough for this call to happen without their input.
Step 11
Repair Fault
Carry out the authorised repair following the manufacturer workshop manual exactly. Genuine or OE quality parts only. All one-use components replaced as standard.
Step 12
Post Fix Operations
All post-repair operations — coding, adaptations, resets, system initialisation, bleeding and road test as required.
Step 13
Confirm Repair
Verify the repair has resolved the original fault. Re-scan for codes. Replicate original conditions and confirm fault-free.
Step 14
Document Repair
Complete the full job card — work carried out, parts used, test results, post-fix operations and confirmation the fault is resolved.
Step 15
CPD
Reflect on the job — what was found, what was learned, what would be done differently next time.
Stage 1 write-up guidance

Completed in the 15-minute window after Step 7. Front of house must be able to read the completed write-up and call the customer without asking the technician a single question.

Stage 1 checklist fields
Did you experience the reported fault?
Answer YES or NO. If NO, explain what conditions were attempted.
Did you do a fault scan?
Answer YES. A full system scan is mandatory on every diagnostic job.
Multiple faults stored — did you delete and road test?
If multiple codes were stored they must be deleted and the vehicle road tested. Answer YES.
Relevant faults returned
Format[Vehicle System] — [Fault Code] — [Fault Description]

ExampleFuel System — P0087 — Fuel Rail Pressure Too Low
TPI found and attached to job sheet?
Answer YES or NO. If YES it must be attached before the write-up is completed.
Stage 1 — the two critical write-up fields
Write-up of work carried out in Stage 1
Formula"Following our test plan we found [what was found], which is caused by [root cause], affecting [which system or component]."

Good example"Following our test plan we found fault code P0087 returning after a road test. Fuel rail pressure is reading below specification under load, caused by a failing high-pressure fuel pump affecting the fuel delivery system. The vehicle is losing power under acceleration as a result."

Not acceptable"Found P0087 stored. Fuel pump suspect."
What are the implications of not doing this work
Formula"If this work is not carried out, the customer risks [safety risk or further damage], which could result in [consequence]."

Good example"If this work is not carried out, the customer risks the high-pressure fuel pump failing completely, which could result in the vehicle breaking down without warning. A failed pump can also contaminate the fuel injectors, turning a single component repair into a significantly more expensive job."

Not acceptable"Vehicle will break down."
Stage 2 test plan — list all tests to be carried out
Good exampleCarry out resistance and voltage drop test on fuel pump circuit wiring
Test fuel pump relay operation and power supply to pump
Measure fuel pump current draw under operating conditions
Carry out injector balance test across all four cylinders

Not acceptableCheck fuel system / Test wiring / Further investigation required
Stage 2 write-up guidance

Completed immediately after Step 9. The same standard applies — front of house must be able to read the Stage 2 write-up and sell the Stage 3 repair without asking the technician anything.

Stage 2 confirmed diagnosis write-up
Summary of tests carried out and results found
Formula"We carried out [test name] which confirmed [result]. Based on these results we can confirm that [root cause]."

Good example"We carried out a fuel pump current draw test which confirmed the pump is drawing above the specified current, indicating internal wear. We carried out a fuel pressure hold test which confirmed pressure drops off significantly after the engine is switched off, confirming the pump check valve has failed. Based on these results we can confirm the high-pressure fuel pump requires replacement."

Not acceptable"Pump tested, confirmed faulty."
What are the implications of not carrying out the repair
Formula"Now that we have confirmed the root cause, if this repair is not carried out the customer risks [consequence], which could result in [outcome]."
What good looks like

A correctly completed Auto IQ diagnostic job produces two written outputs — a Stage 1 write-up and a Stage 2 write-up — both of which front of house can use to contact the customer and sell the next stage without asking the technician a single question. Every conclusion is supported by measured test results. Every implication is stated in plain language the customer can understand.

Time targets
  • Stage 1 technical evaluation: 45 minutes
  • Stage 1 Garage Hive write-up: 15 minutes
  • Stage 1 total: 1 hour
  • Stage 2 and Stage 3: quoted and agreed with the customer before beginning
CPD — Step 15
Current approach

CPD is currently a general ongoing development activity at Fergies. Technicians are encouraged to reflect on completed diagnostic jobs and discuss learning points with the Workshop Manager. Formal per-job recording is not yet mandatory.

Future direction — per-job CPD notes

The intention is to move to a per-job CPD note recorded in Garage Hive against every diagnostic job. Three questions answered honestly: what did I find and how did the process lead me to the correct conclusion, was there anything I could have done more efficiently, and what would I do differently next time with a similar fault.

Common errors and how to avoid them
Skipping steps because the fault seems obvious
Error: Jumping to Step 7 because a fault code points to a specific component.

How to avoid: Always follow the full process from Step 1. A familiar fault code does not guarantee a familiar root cause.
Vague Stage 1 write-ups
Error: Writing "fault code found, further investigation required" as the Stage 1 output.

How to avoid: Use the formula. Every write-up must include what was found, the root cause, the affected system and the implication of not acting.
Starting Stage 2 before authorisation
Error: Beginning Stage 2 tests before front of house has confirmed customer authorisation on the job card.

How to avoid: Wait for front of house to update the job card. Never assume the customer will agree.
Vague Stage 2 test plans
Error: Listing "check fuel system" or "test wiring" as Stage 2 tests.

How to avoid: Every test in the Stage 2 plan must name the specific test, the specific circuit or component and the specific measurement to be taken.
Guessing root cause when tests are inconclusive
Error: Writing a confirmed diagnosis when the test results do not definitively support it.

How to avoid: If the process does not confirm root cause, escalate to the Workshop Manager rather than assuming. A wrong diagnosis is worse than an honest inconclusive result.
Skipping post-fix operations
Error: Completing the repair but not carrying out all required coding, adaptations and resets.

How to avoid: Post-fix operations are as important as the repair itself. Refer to the manufacturer workshop manual for the full list of required post-repair steps for every job.
Communicating findings to the customer directly
Error: Telling the customer what was found, what it will cost or what needs to happen next.

How to avoid: All customer communication goes through front of house at every stage without exception.
Not completing CPD
Error: Closing the job without reflecting on the diagnostic process.

How to avoid: CPD is the last step of every diagnostic job. Even a brief reflection builds diagnostic knowledge over time.
Related SOPs
  • SSS Health Check Procedure — the SSS check is carried out on every vehicle including those booked in for diagnostics
  • Quality Control and Sign-off SOP — sign-off requirements for completed diagnostic jobs
  • Workshop COSHH Register — handling requirements for hazardous substances used during diagnostic and repair work
  • Ramp Operating Procedure — correct ramp use and safety requirements for underside diagnostic work
External references
  • Manufacturer workshop manuals — vehicle-specific diagnostic procedures, torque specifications and post-repair requirements
  • Manufacturer technical information portals — TSBs, TPIs and known fault data
  • Garage Hive — the CRM platform where all diagnostic outputs are recorded
Version and ownership
SOP title
Auto IQ 15-Stage Diagnostic Process
SOP reference
WS-002
Department
Workshop
SOP owners
Workshop Manager and Owner jointly
Review trigger
When something changes or a problem is identified
Status
Live
Version history

Version history will be recorded here as this SOP is reviewed and updated. Each entry should note the date of the change, what changed and who approved it.