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TIAGO AMT Gasoline
DTC Troubleshooting Guide
Version: 2.0
Date: 06-06-2016
Author: Sathi/Anupama
Page: 288 of 424
Copyright ©
TATA MOTORS Ltd.
This document must not be used in any way, such as copying and redistributing to third parties, without the consent of author.
90.
P0780- 07: Hydraulic Circuit System Misuse
Overview:
ISO Code
P0780-07
Customer Symptom
Malfunction in manual upshift/downshift,
earlier/late upshifts/downshifts,
jerky/sluggish gear shifting,
sudden shift to neutral while driving,
No gearshifts
Fault Effects (On Vehicle)
Malfunction in manual upshift/downshift,
earlier/late upshifts/downshifts,
jerky/sluggish gear shifting,
sudden shift to neutral while driving,
No gearshifts
Lamp Status (If Any)
Transmission Fault Lamp ON if level 2 or 3 error(higher in
severity)
Fault Detection Condition
This fault gets detected after Ignition On when gear shifts are
not in progress but TCU detects that:
a> Pump Temperature exceeds a threshold AND
b> In manual mode, Driver is requesting more number of
gearshifts within a time window than a threshold OR
c> In Auto mode, driver is continuously
pressing/releasing throttle
Normal Operating Condition
Pump temperature is below a threshold and Driver shift
requests do not exceed a threshold in a time span window.
Probable Trouble Area
Improper Driving habits /TCU/kit
Healing Condition
10 milliseconds after valid sensor signal
Component Details:
In an AMT system, the hydraulic pump is driven by the TCU whenever the hydraulic pressure read by sensor drops below a
threshold. In case the driver requests gearshifts too frequently than normal driving conditions, the pump has to activate more
frequently and may lead to overheating.
Preliminary Checks:
1) Loose/ Damaged Connections of Electric Motor and TCU
2) Check for damage or back out of pins at TCU connector, electric motor connector.
3) Check visibly for kit Oil leakage and oil level.
4) Check Battery voltage and state of charge.
5) Check for mechanical damage to the gearbox loose or damaged valve body/TCU mountings, Hydraulic
tank/accumulator, Connecting pipes mechanical fitments
6) Check correct fitment of ground cable connections on vehicle chassis.
Trouble Shooting:-
Step Checks
IF YES
IF NO
1
Is the DTC occurring in combination with
- P0820/821/822/823/825,
P0945, P0942 or P2712?
Go to Step 2
2
At first occurrence of the problem, clear the
DTC and drive the vehicle in all gears for
about 10 km simulating /in real dense
traffic condition requiring frequent
gearshifts , does the DTC recur?
Go to Step 3
Release vehicle to the
customer after final drive
test
3
Check Hydraulic pressure sensor and relay
electrical connections by following same
P0932 & P185C
Go to Step 4
Establish continuity by
rectifying harness