Isuzu KB P190. Manual — part 952

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–22

negative number indicates that short shifts have been detected and PC solenoid pressure has been subtracted to
increase shift time.

A/C Clutch: This parameter displays the condition of the sirconditioning compressor as either On or Off.

AT Output Speed: This parameter displays the rotational speed of the transmission output shaft. Tech 2 displays output
shaft speed as revolutions per minute (RPM).

Commanded Gear: This parameter displays the current commanded state of the shift solenoid valves. Tech 2 displays 1,
2, 3 or 4.

Current TAP Cell: This parameter displays the current transmission adaptive pressure (TAP) cell in use for transmission
line pressure adaptation. The cells are based on 17 Nm of engine torque. The higher the engine torque, the higher the
current TAP cell. The last cell used will remain displayed until the next adaptable upshift occurs.

Engine Coolant Temperature: This parameter displays the input signal from the engine coolant temperate (ECT)
sensor. ECT is high at 151°C when the signal voltage is low, 0 V. ECT is low at -40°C when the signal voltage is high,
5 V.

Engine Speed: This parameter displays the rotational speed of the engine expressed as revolutions per minute.

Engine Torque: This parameter displays the calculated value based on engine load, throttle position, mass air flow, and
other engine inputs. This parameter is accurate to within 20 Nm of actual measured engine torque.

Estimated Gear Ratio: This parameter displays the estimated turbine speed divided by the transmission output speed.
Estimated turbine speed is calculated from engine speed and engine torque.

Ignition Voltage: This parameter displays the system voltage measured at the ignition feed.

Latest Shift: This parameter displays the actual time of the last upshift. This value is only accurate if the shift was
adaptable.

PCS Actual Current: This parameter displays the current flow through the pressure control solenoid circuit, which is
measured by the control module. High current flow results in low line pressure. Low current flow results in high line
pressure.

PCS Duty Cycle: This parameter displays the commanded state of the pressure control solenoid, expressed as a
percentage of energised on time. A reading of low percent indicates zero on time, non-energised, or no current flow. A
high percent at idle indicates maximum on time, energised, or high current flow.

PCS Desired Current: This parameter displays the commanded current of the pressure control solenoid circuit. High
current results in low line pressure. Low current results in high line pressure.

Shift Pattern: This parameter displays Normal, Power or Cruise depending on what mode the transmission is in.

Shift Solenoid A: This parameter displays the commanded state of the 1-2 shift solenoid valve. When the transmission
is in 1

st

and 4

th

gear, the display should indicate On; current is flowing through the solenoid. When the transmission is in

2

nd

and 3

rd

gear, the display should indicate Off; current is not flowing through the solenoid.

Shift Solenoid A Circuit: This parameter displays whether an open or a short to ground, short to battery or the circuit is
okay in the 1-2 shift solenoid valve feedback signal. The 1-2 shift solenoid valve must be commanded off and on.

Shift Solenoid B: This parameter displays the commanded state of the 2-3 shift solenoid valve. When the transmission
is in 1

st

and 4

th

gear, the display should indicate On; current is flowing through the solenoid. When the transmission is in

2

nd

and 3

rd

gear, the display should indicate Off; current is not flowing through the solenoid.

Shift Solenoid B Circuit: This parameter displays whether an open or a short to ground, short to battery or the circuit is
okay in the 2-3 shift solenoid valve feedback signal. The 2-3 shift solenoid valve must be commanded off and on.

Speed Ratio: This parameter displays the calculated speed ratio of the transmission.

TCC Duty Cycle Circuit: This parameter displays whether an open or a short to ground, short to battery or the circuit is
okay in the TCC PWM solenoid valve feedback signal. The TCC PWM solenoid valve must be commanded off and on.

TCC Solenoid: This parameter displays the commanded sate of the TCC solenoid. On indicates a commanded
energised state; current is flowing through the solenoid. Off indicates a commanded non-energised state; current is not
flowing through the solenoid. This commanded state occurs at various vehicle speeds between applications.

TCC Slip Speed: This parameter displays the difference between transmission output speed and engine speed. A
negative value indicates the engine speed is less than the output speed, deceleration. A positive value indicates the
engine speed is greater than the output speed, acceleration. A value of zero indicates the engine speed is equal to the
output speed, TCC applied.

TCC PWM Solenoid: This parameter displays the commanded percentage of on time for the TCC PWM solenoid. A high
percentage represents an on, energised, commanded state.0 percent represents an off, non-energised, commanded
state.

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–23

TFP Gear: This parameter displays Park/Neutral, Reverse, Drive4, Drive3, Drive2, Drive1 or Invalid. This parameter
is the decoded status of the three A/B/C inputs from the automatic transmission fluid pressure manual valve position
switch. If a valid combination of inputs is not detected, invalid will be displayed.

TFP Swi A/B/C: This parameter displays Open 12 V / Closed 0 V for each switch. This parameter indicates the statues
of the three inputs from the automatic transmission fluid pressure manual valve position switch assembly.

Throttle Position: This parameter displays a calculated value, which is determined by the accelerator pedal position and
the actual throttle position, used to optimise transmission controls. It represents the driver’s intended requested for
torque or acceleration. The range is 0-100%, 0% represents an idle or coast request and 100% represents a request for
wide open throttle (WOT).

Torque Converter Efficiency: This parameter displays a ratio of 0.00:1 to 2:1. The ratio is calculates by multiplying the
speed ratio by a value related to the ‘K factor’ of the torque converter. The ‘K factor’ is the looseness or tightness of the
torque converter for a given torque. The nearer the torque converter is to full coupling, i.e. 1:1, the closer the torque
converter efficiency number will be to 1.

TR Switch A/B/C/P: This parameter displays the status of the four inputs from the transmission range switch. Tech 2
displays Open 12V / Closed 0 V. Open 12 V indicates an ignition voltage input to the control module. Closed 0 V
indicates a zero voltage input to the control module.

Transmission Fluid Temperature: This parameter displays the input signal of the transmission fluid temperature sensor.
Transmission fluid temperature is high, 151°C, when signal voltage is low, 0 V. Transmission fluid temperature is low, -
40°C, when signal voltage is high, 5 V.

Transmission Hot Mode: This parameter displays the automatic transmission fluid temperature (TFT) and displays On
or Off. Off indicates the TFT has not exceeded 130°C. On indicates the TFT has exceeded 130°C and has not cooled to
120°C for greater than 5 seconds. These numbers are approximate and differ with transmissions.

Vehicle Speed: This parameter displays the speed at which the vehicle is travelling. Tech 2 displays vehicle speed as
kilometres per hour (km/h). The vehicle speed is calculates based on the input signal from the automatic transmission
output shaft speed sensor.

3.4 Miscellaneous

Tests

Tech 2

Miscellaneous Tests

Description

Shift Solenoid A

•

The TCM commands the 1-2 shift solenoid valve on and off. Tech 2’s Shift Solenoid A
Parameter should match the commanded state. Tech 2’s Commanded Gear
parameter should correspond with the shift solenoid combination. Refer to
5.6 Shift Solenoid Valve State and Gear Ratio.

•

When the ignition is on, and the engine is off, there no limits to this control. The
solenoid remains on until commanded off, and vice versa. When the test is exited, the
solenoid state is determined by the TCM.

•

When the engine is running, the following control limits apply:

•

Only sequential gear changes are allowed. For example, 1

st

to 3

rd

is not allowed.

If a non-sequential gear change is attempted, the message Non-sequential
gear changes not allowed. Gear changes must be made in order appears
on Tech 2.

•

The vehicle speed must be below a calibrated value. If the vehicle speed is too
high, the message Vehicle speed too high appears on Tech 2.

•

The engine speed must be below a calibrated value. If the engine speed is too
high, the message Engine speed too high appears on Tech 2.

•

Downshifts are allowed only when the vehicle speed is below a calibrated value.
If the vehicle speed is too high, the message Eng. is on and veh. speed to hi
for 3-2 or 2-1 downshift appears on Tech 2.

•

The gear requested may not be greater than the current selected transmission
range (PRNDL). For example, 3

rd

gear is not allowed if the transmission range is

D2. If the gear requested is greater than the current selected transmission
range, the message Eng. running and gear request is greater than the
current TR appears on Tech 2.

•

The solenoid remains on until commanded off, and vice versa. When the test is
exited, the solenoid state is determined by the TCM.

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–24

Shift Solenoid B

•

The TCM commands the 2-3 shift solenoid valve on and off. Tech 2’s Shift Solenoid B
parameter should match the commanded state. Tech 2’s Commanded Gear
parameter should correspond with the shift solenoid combination. Refer to
5.6 Shift Solenoid Valve State and Gear Ratio.

•

When the ignition is on, and the engine is off, there no limits to this control. The
solenoid remains on until commanded off, and vice versa. When the test is exited, the
solenoid state is determined by the TCM.

•

When the engine is running, the following control limits apply:

•

Only sequential gear changes are allowed. For example, 1

st

to 3

rd

is not allowed.

If a non-sequential gear change is attempted, the message Non-sequential
gear changes not allowed. Gear changes must be made in order appears
on Tech 2.

•

The vehicle speed must be below a calibrated value. If the vehicle speed is too
high, the message Vehicle speed too high appears on Tech 2.

•

The engine speed must be below a calibrated value. If the engine speed is too
high, the message Engine speed too high appears on Tech 2.

•

Downshifts are allowed only when the vehicle speed is below a calibrated value.
If the vehicle speed is too high, the message Eng. is on and veh. speed to hi
for 3-2 or 2-1 downshift appears on Tech 2.

•

The gear requested may not be greater than the current selected transmission
range (PRNDL). For example, third gear is not allowed if the transmission range
is D2. If the gear requested is greater than the current selected transmission
range, the message Eng. running and gear request is greater than the
current TR appears on Tech 2.

•

The solenoid remains on until commanded off, and vice versa. When the test is
exited, the solenoid state is determined by the TCM.

3-2 Downshift Solenoid

•

The TCM commands the 3-2 shift solenoid valve on and off. Tech 2’s 3-2 Downshift
Sol. parameter should match the commanded state.

•

When the ignition is on, and the engine is off, there are no limits to this control. The
solenoid remains on until commanded off, and vice versa. When the test is exited, the
solenoid state is determined by the TCM.

•

When the engine is running, the following control limits apply:

•

The transmission range (PRNDL) must be Park or Neutral. If the transmission
range is not in Park or Neutral, the message :Engine running and
transmission range is not Park/Neutral appears on Tech 2.

•

The solenoid remains on until commanded off, and vice versa. When the test is
exited, the solenoid state is determined by the TCM.

Clear TAPS

(Transmission Adaptive
Pressures)

•

The TCM clears (or resets) the TAP cells to the original base value.

•

There are no limits to using this test. It may be performed with the engine running or
when the ignition is on, and the engine is off.

Automatic Transmission – 4L60E – Electrical Diagnosis

Page 7C2–25

PC Solenoid

•

The TCM commands the current to the pressure control solenoid to control
transmission line pressure. As the current increases, the line pressure decreases. As
the current decreases, the line pressure increases. The current range is 0.00 – 1.10 A
and may be commanded in one-tenth of an amp increments.

•

When the ignition is on, and the engine is off, the reference (commanded) amperage
may be controlled within calibrated limits. Tech 2’s parameter PCS Desired Current
changes by the parameter PCS Actual Current does not change. The reference
current remains until commanded otherwise.

•

When the engine is running, the following control limits apply:

•

When the transmission range is Park or Neutral, the reference (commanded)
current may be controlled within calibrated limits. The engine speed must be
less than 1,500 r.p.m. If the engine speed is great than 1,500 r.p.m, the
message TR in park/neutral and engine speed over 1,500 RPM appears on
Tech 2. Both Tech 2 parameters PCS Desired Current and PCS Actual Current
parameters change. Both current readings remain until commanded otherwise.

•

When the transmission range is not in Park or Neutral, the reference current can
only be controlled less than the current determined by the TCM. The TCM does
not allow a value to be selected that may cause damage to the transmission. If
the requested amperage is more than allowed by the TCM, the message
Requested current for the PC Solenoid is too high appears on Tech 2.

•

Transmission range DTCs must not be active. If a transmission range DTC is
active, the message Engine running with transmission DTC present appears
on Tech 2.

Gear Control

•

The TCM commands upshifts and downshifts. Tech 2’s Commanded Gear parameter
should correspond with the shift solenoid combination. Refer to 5.6

Shift

Solenoid Valve State and Gear Ratio.

•

When the ignition is on, and the engine is off, there are no limits to this control. The
Tech 2 shift solenoid states changes to match the Commanded Gear selected.

•

When the engine is running, the following control limits apply:

•

The TCM does not allow a shift if it causes the engine r.p.m. to exceed a
calibrated limit. If a gear is requested and the engine speed is too high, the
message Engine speed too high appears on Tech 2.

•

The TCM does not allow a 3-2 or 2-1 downshift if the vehicle speed exceeds a
calibrated limit. If either downshift is requested and the vehicle speed is too high,
the message Eng. is on and veh. Speed too hi for 3-2 or 2-1 downshift
appears on Tech 2.

•

The TCM does not allow a 4-3 downshift if this vehicle speed exceeds a
calibrated limit. If a 4-3 downshift is requested and the vehicle speed is too high,
the message Vehicle speed to high appears on Tech 2.

•

The TCM does not allow an upshift if the vehicle speed exceeds a calibrated
limit. If an upshift is requested and the vehicle speed is too high, the message
Vehicle speed to high appears on Tech 2.

•

The TCM does not allow an upshift that is greater than the current selected
transmission range (PRNDL). For example 3

rd

gear is not allowed if the

transmission range is D2. If an upshift is requested that is greater than the
current selected transmission range, the message Eng. running and gear
request is greater than the current TR appears on Tech 2.