Isuzu Trooper (1998-2002 year). Manual - part 795

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–89

DTC P1870 Transmission Component Slipping (TCC Stuck OFF)

D07R200051

Circuit Description

The PCM monitors the difference in engine speed and
transmission output speed. For example in D3 drive
range with the ECCC commanded, the engine speed
should closely match transmission output speed.
This DTC detects excessive TCC slip when the ECCC is
engaged.  This is a type “B” DTC.

Conditions For Setting The DTC

The following conditions are met for three TCC cycles
with reported excessive TCC slip conditions.

D

No OSS DTCs P0722 or P0723.

D

No shift solenoid A DTCs P0751 or P0752 or P0753.

D

No shift solenoid B DTCs P0756 or P0757 or P0758.

D

No TCC solenoid DTCs P0742 or P1860 or P1870.

D

Engine speed is between 1,000 and 3,500 rpm for 0.5
seconds.

D

Gear range is D4.

D

13% < TPS < 99%

D

50 < Engine Torque < 300 N·m

D

TFT is between 20

°

 and 150

°

C (68

°

 and 302

°

F).

D

TCC slip speed is between 250 rpm and 800 rpm for 3
times 7 seconds.

D

Vehicle speed is between 25 km/h (15 mph) and 225
km/h (158 mph).

D

Speed ratio is between 0.6 and 0.95.

D

ECCC is “ON”.

D

Low (0.8) < TCC Capacity < hi (0.99) for 5 seconds

Action Taken When The DTC Sets

D

Only stored in memory.

D

For lamp illuminate refer to DTC type definition (type
B).

Conditions For Clearing The MIL/DTC

D

The PCM will turn off the MIL and CHECK TRANS
Lamp after three consecutive ignition cycles without a
failure reported.

D

The DTC can be cleared from the PCM history by
using a scan tool.  

D

The DTC will be cleared from history when the vehicle
has achieved 40 warmup cycles without a failure
reported.

D

The PCM will cancel the DTC default actions when
the fault no longer exist and the ignition is cycled “off”
long enough to power down the PCM.

Diagnostic Aids

D

Range switch malfunction could set a DTC P1870.

D

A mechanical failure of the shift solenoids, TCC
solenoid, or TCC PWM solenoid could set a DTC
P1870.

D

Internal transmission failures may set a DTC P1870.

D

An intermittent or incorrect engine speed signal may
set a DTC P1870.

7A1–90 TRANSMISSION CONTROL SYSTEM (4L30–E)

Test Description

The numbers below refer to the step numbers on the
diagnostic chart:
2. This test checks the indicated range signal to the

actual selected range.  A faulty switch could set a
DTC P1870.

3. This test checks the torque converter for slippage

while in a commanded lockup state.

Range Switch Logic Table

Range

Range Switch Pin

g

Position

A

B

C

P(G)

Park

ON

OFF

OFF

ON

Reverse

ON

ON

OFF

OFF

Neutral

OFF

ON

OFF

ON

D4

OFF

ON

ON

OFF

D3

ON

ON

ON

ON

2

ON

OFF

ON

OFF

L

OFF

OFF

ON

ON

Illegal

OFF

OFF

OFF

OFF

Illegal

OFF

OFF

OFF

ON

DTC P1870 Transmission Component Slipping (TCC Stuck OFF) 

Step

Action

Yes

No

1

Were you sent here from the “Powertrain On–Board Diagnostic
(OBD) System Check”?

Go to Step 2

Go to OBD

System Check

Refer to

Driveability and

Emissions in

Engine section

2

1. Install the scan tool.
2. With the engine “off”, turn the ignition switch “on”. 

NOTE: Before clearing DTC(s), use the scan tool to record “Freeze
Frame” and “Failure Records” for reference, as data will be lost
when the “Clear Info” function is used.

3. Record the DTC “Freeze Frame” and “Failure Records”.
4. Apply the brake pedal.
5. Select each transmission range: DL, D2, D3, D4, N, R, and P.

Does each selected transmission range match the scan tool “TR
Switch” display?

Go to Step 3

Go to “Range

Switch Logic

Table”

3

Drive the vehicle in 4th gear while the TCC is engaged.

At any time is the “TCC Slip Speed” greater than 130 rpm for 8
seconds while the TCC is engaged?

Go to System

Diagnosis Charts

Go to Diagnostic

Aids

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–91

Circuit Diagram (LHD)

D07R200037

7A1–92 TRANSMISSION CONTROL SYSTEM (4L30–E)

D07R200038