Isuzu Rodeo UE. Manual - part 491

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–83

DTC P1860 TCC Solenoid Electrical

D07RW016

Circuit Description

The PCM allows current to flow through the solenoid coil.
This current flow through the solenoid coil creates a
magnetic field that magnetizes the solid core.  The
magnetized core attracts the check ball to seat against
spring pressure.  This blocks the exhaust for the TCC
signal fluid and allows 2–3 drive fluid to feed to TCC signal
circuit.  The TCC signal fluid pressure acts on the TCC
regulator valve to regulate line pressure and to apply fluid
pressure to the torque converter clutch shift valve.  When
the TCC shift valve is in the apply position, regulated
apply fluid pressure is directed through the TCC valve to
apply the torque converter clutch.  The TCC solenoid is
used in conjunction with the TCC solenoid to regulate fluid
to the torque converter.  The TCC solenoid is attached to
the valve body within the transmission.
This DTC detects a continuous open or short to ground or
ignition in the TCC circuit or the TCC solenoid.  This is a
type “B” DTC.

Conditions For Setting The DTC

f

Battery voltage is between 10 and 16 volts.

f

No shift solenoid A DTCs P0751 or P0753.

f

No shift solenoid B DTCs P0756 or P0758.

f

Ignition “on”. Engine “run”.

f

The PCM commands the solenoid “on” and the
voltage remains low (zero volts).

f

The PCM commands the solenoid “off” and the
voltage remains high (B+).

f

All conditions met for 0.25 seconds.

Action Taken When The DTC Sets

f

Inhibit TCC engagement.

f

The PCM will illuminate the Malfunction Indicator
Lamp (MIL) and CHECK TRANS Lamp.

Conditions For Clearing The MIL/DTC

f

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

f

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

f

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

f

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

Diagnostic Aids

f

Inspect the wiring for poor electrical connections at
the PCM and at the transmission 16–way connector.
Look for possible bent, backed out, deformed or
damaged terminals.  Check for weak terminal tension
as well.  Also check for a chafed wire that could short
to bare metal or other wiring.  Inspect for a broken wire
inside the insulation.

f

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.

Test Description

The numbers below refer to the step numbers on the
diagnostic chart:
3. This test checks for voltage to the solenoid.
4. This test checks the ability of the PCM and wiring to

control the ignition circuit.

9. This test checks the resistance of the TCC solenoid

and the internal wiring harness.

7A1–84 TRANSMISSION CONTROL SYSTEM (4L30–E)

DTC P1860 TCC Solenoid Electrical 

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

Emission in

Engine section

2

1. Install the scan tool.
2. With the engine “on”, 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”.

Go to Step 3

Go to Step 4

3

Using the J39200 DVOM, back probe between PCM connector
terminals C2–D2 and C2–C8.

Is the voltage 0?

Go to Step 5

Go to Step 6

4

1. Apply brake pedal and select transmission range “D”.
2. Do a test drive, and increase the vehicle speed to TCC “on” at

4th.

Does the scan tool display DTC P1860 at TCC “ON”?

Go to Step 10

Go to Diagnostic

Aids

5

1. Turn the ignition “off”.
2. Disconnect the C2 (WHITE) PCM connector.
3. Using the J39200 DVOM, measure the resistance between

PCM connector terminals C2–D2 and C2–C8.

Is the resistance within 18 – 20 ohms?

Go to Step 7

Go to Step 8

6

The wiring harness between PCM connector terminal C2–D2 and
transmission adapter case connector terminal M6–4(A) is shorted
to voltage.

Was a problem found and corrected?

Go to Step 19

Go to Step 20

7

Intermittent condition.
Check the wiring harness and terminals between PCM connector
J2 and transmission adapter case connector M–6.

Was a problem found and corrected?

Go to Step 19

Go to Step 20

8

1. Disconnect the transmission 16–way connector H–10.
2. Using the J39200 DVOM, measure the resistance between

terminal H10–4 and ground.

Is the resistance within 18 – 20 ohms?

Go to Step 16

Go to Step 9

9

1. Disconnect the transmission adapter case connector M–6.
2. Using the J39200 DVOM, measure the resistance between

terminal M6–4(A) and ground.

Is the resistance within 18 – 20 ohms?

Go to Step 17

Go to Step 18

10

1. Turn the ignition “off”.
2. Disconnect the C2 (WHITE) PCM connector.
3. Using the J39200 DVOM, measure the resistance between

terminals C2–D2 and C2–C8.

Is the resistance within 18 – 20 ohms?

Go to Step 19

Go to Step 11

TRANSMISSION CONTROL SYSTEM (4L30–E)

7A1–85

DTC P1860 TCC Solenoid Electrical  (Cont’d)

Step

No

Yes

Action

11

1. Disconnect the transmission 16–way connector H–10.
2. Using the J39200 DVOM, measure the resistance between

terminal H10–4 and ground.

Is the resistance within 18–20 ohms?

Go to Step 13

Go to Step 12

12

1. Disconnect the transmission adapter case connector M–6.
2. Using the J39200 DVOM, measure the resistance between

terminal M6–4(A) and ground.

Is the resistance within 18–20 ohms?

Go to Step 14

Go to Step 15

13

The wiring harness between PCM connector terminal C2–D2 and
transmission 16–way connector terminal H10–4 is shorted to
ground.

Was a problem found and corrected?

Go to Step 21

—

14

The wiring harness between transmission 16–way connector
H–10 and adapter case connector M–6 is shorted to ground.

Was a problem found and corrected?

Go to Step 21

—

15

The TCC solenoid is faulty, or the internal wiring harness from the
TCC solenoid is shorted to ground.

Was a problem found and corrected?

Go to Step 21

—

16

The wiring harness between PCM connector terminal C2–D2 and
transmission 16–way connector terminal H10–4 is open.

Was a problem found and corrected?

Go to Step 21

—

17

The wiring harness between transmission 16–way connector
terminal H10–4 and adapter case terminal M6–4(A) is open.

Was a problem found and corrected?

Go to Step 21

—

18

The TCC solenoid is faulty, or the internal wiring harness from the
TCC solenoid is open.

Was a problem found and corrected?

Go to Step 21

—

19

Check every connection at the PCM.
If OK, replace the PCM. Refer to Powertrain Control Module
(PCM) in Automatic Transmission (4L30–E) section.

Is the replacement complete?

Go to Step 21

—

20

Check the PCM connector terminal C2–D2, transmission 16–way
connector terminal H10–4 and transmission adapter case
connector terminal M6–4(A).

Was a problem found and corrected?

Go to Step 21

—

21

1. After the repair is complete, use the scan tool to select “DTC”,

then “Clear Info” function and ensure the following conditions
are met:

f

The TCC solenoid is commanded “on” and the volts increase
to B+.

f

The TCC solenoid is commanded “off” and the volts drop to
zero.

2. Review the scan tool “DTC Info”.

Has the last test failed or is the current DTC displayed?

Begin diagnosis

again

Go to Step 1

Repair verified
Exit DTC table

7A1–86 TRANSMISSION CONTROL SYSTEM (4L30–E)

DTC P1870 Transmission Component Slipping

D07RW023

Circuit Description

The PCM monitors the difference in engine speed and
transmission output speed.  In D3 drive range with the
TCC engaged, the engine speed should closely match
transmission output speed.
This DTC detects excessive TCC slip when the TCC 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.

f

No TP DTCs P0122 or P0123.

f

No OSS DTCs P0722 or P0723.

f

No shift solenoid A DTCs P0751 or P0753.

f

No shift solenoid B DTCs P0756 or P0758.

f

No TCC PWM solenoid DTC P1860.

f

No TCC solenoid DTC P0742.

f

Engine speed is between 800 and 3,360 rpm.

f

Engine vacuum is between 0 and 70 kPa.

f

Gear range is D4.

f

TP angle is between 12 and 70%.

f

TFT is between 20

°

 and 141

°

C (68

°

 and 286

°

F).

f

TCC is “on” for 3 seconds.

f

TCC slip speed is between 200 rpm and 800 rpm for
10 seconds.

f

Vehicle speed is between 38 km/h (24 mph) and 110
km/h (69 mph).

f

Speed ratio is between 0.6 and 0.95.

f

No MAP DTCs P0106 or P1106 or P0107 or P1107 or
P0108.

Action Taken When The DTC Sets

f

Only stored in memory.

f

The PCM will illuminate the Malfunction Indicator
Lamp (MIL) and CHECK TRANS Lamp.

Conditions For Clearing The MIL/DTC

f

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

f

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

f

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

f

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

Diagnostic Aids

f

Range switch malfunction could set a DTC P1870.

f

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

f

Internal transmission failures may set a DTC P1870.