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Isuzu Trooper (1998-2002 year). Manual - part 513

6E–422

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

DTC P1404 – EGR Stuck Closed

(Cont'd)

Step

Yes

Value(s)

Action

Replace the EGR valve.

Does DTC P1404 still fail “DTC” test on the Tech 2?

—

Go to

Step 10

Verify repair

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed. Refer to

On-Vehicle Service in

Powertrain Control Module and Sensors for
procedures.

And also refer to latest Service Bulletin.

Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.

Is the action complete?

—

Verify repair

—

6E–423

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
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

6E–424

6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS

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 – 7 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

Check the

procedure.

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?

∼

7 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

—

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 8

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?

∼

7 g/s

Go to

Step 6

Go to

Step 9

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

Is the MAP reading less than the specified value?

100 kPa

Go to

Step 10

Go to

Step 13

6E–425

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1514 - TPS-MAF Correlation Error

(Cont'd)

Step

Yes

Value(s)

Action

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 11

Go to

Step 18

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 12

Replace the MAP sensor.

Is the action complete?

—

Verify repair

—

1. Warming up the engine until the ECT rise at 80

2. Ignition “OFF”.
3. Ignition “ON” but not engine run.
4. Observe the TP angle reading on the Tech 2 while

alowly opening the throttle.

NOTE: The value check of TPS must be performed in
less than 15 seconds.

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

Closed

throttle
TPS1=
6

∼

12%

TPS2=

∼

94% Wide

open throttle

TPS1=

∼

83%

TPS2=

∼

23%

Go to

Step 18

Go to

Step 14

1. Connect a DVM between the 5Volt reference circuit

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

2. Observe the voltage using a DVM.

Is the voltage near the specified value?

Go to

Step 15

Go to

Step 18

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 16

Check the following items;

1. TP1and TP2 signal circuit or 5 volt reference circuit

for a poor connection.

2. TP1 and TP2 signal circuit or 5 volt reference circuit

for high resistance between the PCM and the
TP1and TP2 sensor.

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

necessary.

Was a problem found?

—

Verify repair

Go to

Step 17

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