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Isuzu Trooper (2000 year). Manual - part 335

6E–469

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1441 – EVAP System Flow During Non-Purge

(Cont'd)

Step

Yes

Value(s)

Action

Replace the Purge Solenoid Valve.

—

Verify Repair

—

1. Check leaks, kinks or pinched hoses at the EVAP

system rubber hose line, and also check if the
rubber hoses are correctly connected or not.

2. Check for a leak from Vent Solenoid Valve and

EVAP system rubber hoses, and also check for
clogged Filter of air separator which is located near
the vent solenoid valve.

Was a problem found? Using the Vacuum Hose
Routing Diagram, repair or re-connect the rubber
hoses correctly.

—

Verify Repair

Go to

Step 7

1. Start engine.
2. Remove the Fuel Filler cap.
3. Using the Tech 2, command the EVAP Vent

Solenoid Valve “ON” (closed) and Purge Solenoid
Valve “OFF” (0%).

4. Replace the Fuel Filler Cap.
5. Run the engine at 2500RPM constant while

monitoring “Fuel Tank Vacuum” on the Tech 2.

Does the fuel tank vacuum remain at the specified
value while the EVAP Vent Solenoid Valve “ON”
(closed) and Purge Solenoid Valve “OFF” (0%)?

30 - 40 %

Verify Repair

Go to

Diagnostic

Aids

6E–470

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P1514 TPS - MAF Correlation Error

D06RY00090

Circuit Description

The throttle position (TP) sensor circuit provides a
voltage signal relative to throttle blade angle.

The throttle blade angle will vary about 8 % at
closed throttle to about 92 % at wide open throttle
(WOT).

The mass air flow (MAF) sensor measures the amount
of air which passes through it into the engine during a
given time. The powertrain Control Module (PCM)
uses the mass air flow information to monitor engine
operating conditions for fuel delivery calculations.

A large quantitiy of air entering the engine
indicates an accleration or high load situation,
while a small quantity or air indicates deceleration
or idle.

The MAF sensor produces a frequency signal
which can be monitored using a Tech 2. The
frequency will vary within a range of around 4 to
7g/s at idle to around 25 to 40g/s at maximum
engine load.

Conditions for setting the DTC

The engine is running.

No MAF sensor DTCs are set.

Throttle actuation mode is not off.

MAF reading-ETC estimated air flow is less than 40g/s
for 250 failres within test 1000 test samples (15.6 m
sec).

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

The PCM calculates an air flow value based on idle air
control valve position, throttle position, RPM and
barometric pressure.

The PCM will store condition which were present when
the DTC was set as Freeze Frame and in the Failure
Records data.

Conditions for Clearing the MIL/DTC

The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condtion is no longer present.

A history DTC P1514 will clear after 40 cosecutive trip
cycle during which the warm up cycles have occurred
without a fault.

DTC P1514 can be cleared using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

An intermittent may be caused by the following:

Poor connectons.

Mis routed harness.

Rubbed through wire insulation.

Broken wire inside the insulation.

Check for the following conditions:

Poor connection at PCM - Inspect harness connectors
for backed out terminals, improper mating,broken

6E–471

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

locks, improperly formed or damaged terminals,and
poor terminal to wire connection.

Damaged harness - Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
Mass Air Flow, TP sensor 1, TP sensor 2 display on the
Tech 2 while moving connectors and wiring harnesses
related to the sensor.

Plugged intake air duct or filter element

A wide - open throttle acceleration from a stop should
cause the mass air flow displayed on a Tech 2 to
increase from about 3 – 6 g/s at idle to 100 g/s or

greater at the time of the 1 – 2 shift. If not, check for a
restriction.

A change in the display will indicate the location of
the fault. If DTC P1514 cannot be duplicated, the
information included in the Faillure Records data
can be useful in determined vehicle mileage since
the DTC was last set.

If it is determined that the DTC occurs
intermittently, performing the DTC P1514
Diagnostic Chart may isolate the cause of the
fault.

DTC P1514 - TPS-MAF Correlation Error

Step

Action

Value(s)

Yes

Was the “On-Board (OBD) System Check” performed?

—

Go to

Step 2

Go to

OBD

System

Check

Was the “Electric Throttle Control (ETC) System
Check” performed?

—

Go to

Step 3

Go to

ETC

System

Check

1. Ignition “ON,” engine “OFF.”
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records

conditions as noted.

4. Using a Tech 2, monitor “DTC” info for DTC P1514.

Does the Tech 2 indicate DTC P1514 failed this
ignition?

—

Go to

Step 4

Refer to

Diagnostic

Aids

1. Start the engine.
2. With the engine idling, monitor “MAF Frequency”

display on the Tech 2.

Is the “MAF Frequency” below the specified value?

∼

10 g/s

Go to

Step 5

Go to

Step 8

1. Ignition “OFF.”
2. Disconnect the MAF sensor connector.
3. Ignition “ON,” engine idling.
4. Using a Tech 2, monitor “MAF Frequency.”

Does the Tech 2 indicate a “MAF Frequency” at the
specified value?

0g/s

Go to

Step 6

Go to

Step 7

Replace the MAF sensor.

Is the action complete?

—

Verify repair

Go to

Step 9

1. Check the MAF harness for incorrect routing near

high voltage components (solenoids, relays,
motors).

2. If incorrect routing is found, correct the harness

routing.

Was a problem found?

—

Verify repair

Go to

Step 7

1. With the engine idling, monitor “MAF Frequency.”

display on the Tech 2.

2. Quickly snap open throttle to wide open throttle

while under a road load and record value.

Does the Tech 2 indicate a “MAF Frequency” at
thespecified value?

∼

10 g/s

Go to

Step 6

Go to

Step 9

6E–472

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1514 - TPS-MAF Correlation Error

(Cont'd)

Step

Yes

Value(s)

Action

1. Ignition“ON”, engine not running.
2. Observe the MAP reading on the Tech 2.

Is the MAP reading less than the specified value?

65kPa

Go to

Step 10

Go to

Step 13

1. Disconnect the MAP sensor.
2. Connect a test 5 volt reference circuit and the MAP

signal at the MAP sensor harness connector.

3. Observe the MAP reading on the Tech 2.

Is the MAP reading less than the specified value? (If no,
start with diagnosis chart for other sensors in the circuit
and see if 5Vreturns.)

—

Go to

Step 12

Go to

Step 11

1. Check the MAP signal circuit between the PCM and

MAP ground circuit.

2. If the MAP signal circuit is open or shoted, repair it

as necessary.

Was the MAP signal circuit open or shorted?

—

Verify repair

Go to

Step 13

Replace the MAP sensor.

Is the action complete?

—

Verify repair

—

Observe the TP angle reading on the Tech 2 while
slowly opening the throttle.

Does the TP angle increase steadily and evenly from
the closed throttle value to the wide open throttle
value?

Closed

throttle TP

sensor 1 =8

∼

10 % TP

sensor 2 =90

∼

92 % Wide

open throttle

TP sensor 1

=90

∼

92 %

TP sensor 2

∼

10 %

Refer to

Diagnostic

Aids

Go to

Step 14

1. Disconnect the TP sensor.
2. Observe the TP sensor reading on the Tech2.

Is the TP sensor reading near the specified value?

Go to

Step 15

Go to

Step 16

1. Connect a test light between the 5Volt reference

circuit and the TP1 and TP2 sensor signal circuit at
the TP sensor harness connector.

2. Observe the TP sensor reading on the Tech2.

Is the TP sensor reading near the specified value?

Go to

Step 18

Go to

Step 17

Check the following items;

1. TP1 and TP2 signal circuit for a short to voltage.
2. TP1 and TP2 sensor ground circuit for high

resistance between the PCM and the TP sensor.

3. TP1 and TP2 sensor ground circuit for a poor

connection.

4. If a problem is found, repair wiring harness as

necessary.

Was a problem found?

—

Verify repair

Go to

Step 19

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