It happens again…

An experienced road tester who was an expert in automatic transmission overhaul…

A master technician who knows this model inside out…

A very intelligent senior technican…

A trainer with a lot of diagnostic experience…

All of them failing to notice something very basic…on the same day, on the same vehicle!

It happened like this…

Day One -10.07 am

Customer complaint: Engine rpm shoots up, Gear stays in 3 while driving.

Customer in a hurry, can not wait for joint road test, leaves the car with the reception and vanishes…

Day One – 12.34 pm

Road tester informs service reception that he could not find any abnormalities.

Day One – 12.45 pm

Service reception requests the customer to provide more details. Customer says he will come to workshop the next day and demonstrate the problem.

Day Two

Customer does not turn up. Phone switched off.

Day Three – 6.09 pm

Customer arrives and goes with a senior technican for a road test. Unable to demonstrate clearly the problem. He says the shift is not  as it was before. And sometimes,  ‘sometimes’, he cannot say when, the gear stays in 3 for a long time before shifting to 4.

Day Four – 8.00 am

No warning lamps, no diagnostic trouble codes [DTC], automatic transmission fluid [ATF] level and condition OK, all inputs and outputs working fine, transmission control module software is the latest…

Senior technician consults one of the experts…

“Valve body re…”  out goes the valve body and a new one comes in…

Day Four – 4.27 pm

Customer is at the workshop to see the progress. Another test drive. He is not satisfied. He can not demonstrate the “rpm shoots up” or “gear stays in 3” problems, but he is sure the shifting remained abnormal…

Day four – 4.50 pm

I join the team…

Another road test with the diagbnostic tool connected…

Transmission control module [TCM] data records taken at different driving conditions…

The records compared with the AT shift pattern for this model…

Shifting abnormal! Shift points, all of them, not matching the shift chart!!

After kickdown, when driving at 60-80 km/hr, the gear stays at 3 for a longer time!

Day 5 – 8.00 am

Transmission fluid pressure test done again… normal readings…

Vehicle speed sensor, Throttle position sensor and turbine speed sensor performance closely monitored. No problems. As specified in the manual…

One of these sensors must be giving wrong inputs while driving…

But no trouble codes…

May be one of the sensors giving confusing, but within limits, reading  so that the PCM…

Oh no! We have not checked the tyres yet!

Front right was 215/50R17 and all others, 225/45R17…

Did this ever happen to you?

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