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Hummer H1 (2002+). Manual - part 270

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PCM/Tech 1 Scan Tool 13

05745159

1. Turn the ignition “ON,” engine “OFF.”
2. Verify the fuel solenoid is still disconnected.

3. Probe ignition feed circuit (terminal D) at the fuel sole-

noid harness connector with a test light connected to
ground.

Is test light “ON”?

—

Go to Step 16

Go to Step 21

Replace fuel injection pump.
Is the action complete?

—

Go to Step 25

—

Injection system OK,

—

Check the fuel inject control circuit for an open or ground
between the fuel solenoid driver and the PCM.
Was a problem found?

—

Go to Step 22

Go to Step 20

Check the closure ground circuit for an open between the
fuel solenoid driver and the PCM.
Was a problem found?

—

Go to Step 22

Go to Step 20

Inspect the fuel solenoid driver connector and PCM con-
nector for proper connection.
Was a problem found?

—

Go to Step 22

Go to Step 24

Repair the open in the ignition feed circuit.
Is action complete?

—

Go to Step 25

—

Repair the circuit as necessary.
Is the action complete?

—

Go to Step 25

—

Make appropriate repairs.
Is action complete?

—

Go to Step 25

—

Replace the faulty PCM.

NOTE:

If the PCM is faulty, the new PCM must be

programmed. Go to PCM replacement and pro-
gramming procedures.

Is the action complete?

—

Go to Step 25

—

1. Using the Scan Tool, select “DTC,” “Clear Info.”
2. Attempt to start engine.

Does the engine start and continue to run?

—

Go to Step 26

Go to Step 2

1. Allow engine to idle until normal operating tempera-

ture is reached.

2. Select “DCT,” “Fail this Ign.”

Are any DTCs displayed?

—

Go to Step 27

—

Using the scan tool, select “Capture Info,” Review Info.”
Are any DTCs displayed that have not been diagnosed?

—

Go to the applica-
ble DTC table

System OK

Engine Cranks But Will Not Start

Step

Action

Value(s)

Yes

PCM/Tech 1 Scan Tool

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DTC (DTC) IDENTIFICATION

The MIL (Service Engine Soon) lamp will be “ON” if an emis-
sion malfunction exists. If the malfunction clears, the lamp will
go “OFF” and the DTC will be stored in the PCM. Any DTCs
stored will be cleared if no problem recurs within l50 engine
starts.

• All DTCs with the sign * are transmission related DTCs

and have descriptions, diagnostic charts are in Section 5.
Remember, always start with the lowest numerical en-
gine DTC first. When diagnosing some engine DTCs,
other transmission symptoms can occur.

Intermittents

A corresponding DTC will be stored in the memory of the
PCM as a history DTC until DTCs have been cleared. When
unexpected DTCs appear during the code reading process, one
can assume that these DTCs were set by an intermittent mal-
function and could be helpful in diagnosing the system. An in-
termittent DTC may or may not re-set. If it is an intermittent
failure, a Diagnostic Trouble Code (DTC) chart is not used.
Consult the “Diagnostic Aids” on the page facing the diagnos-
tic chart corresponding to the intermittent DTC. Section “2”
also covers the topic of “Intermittents”. A physical inspection
of the applicable sub-system most often will not resolve the
problem.

Scan Tool Use With Intermittents

In some scan tool allocations, the data update rate makes the
tool less effective than a voltmeter, such as when trying to de-
tect an intermittent problem which lasts for a very short time.
However, the scan tool allows manipulation of wiring har-
nesses or components under the hood with the engine not run-
ning, while observing the scan tool readout.

The scan tool can be plugged in and observed while driving the
vehicle under the condition when the MIL “Service Engine
Soon” light turns “ON” momentarily or when the engine drive-
ability is momentarily poor. If the problem seems to be related
to certain parameters that can be checked on the scan tool, they
should be checked while driving the vehicle. If there does not
seem to be any correlation between the problem and any spe-
cific circuit, the scan tool can be checked on each position,
watching for a period of time to see if there is any change in the
reading that indicates intermittent operation.

The scan tool is also an easy way to compare the operating pa-
rameters of a poorly operating engine with those of a known
good one. For example, a sensor may shift in value but not set a
DTC. Comparing the sensor’s readings with those of a known
good vehicle may uncover the problem.

The scan tool has the ability to save time in diagnosis and pre-
vent the replacement of good parts. The key to using the scan
tool successfully for diagnosis lies in the technician’s ability to
understand the system he is trying to diagnose as well as under-
standing of the scan tool operation and limitations. The techni-
cian should read the tool manufacturer’s operating manual to
become familiar with the tool’s operation.

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PCM/Tech 1 Scan Tool 15

05745159

Diagnostic Trouble Code (DTC) Identification

DTC

Description

Type

Illuminate MIL

P0112

IAT Sensor Circuit Low Voltage

Yes

P0113

IAT Sensor Circuit High Voltage

Yes

P0117

ECT Sensor Circuit Low Voltage

Yes

P0118

ECT Sensor Circuit High Voltage

Yes

P0121

APP Sensor 1 Circuit Performance

P0122

APP Sensor 1 Circuit Low Voltage

P0123

APP Sensor 1 Circuit High Voltage

P0182

Fuel Temperature Sensor Circuit Low Voltage

Yes

P0183

Fuel Temperature Sensor Circuit High Voltage

Yes

P0215

Engine Shutoff Control Circuit

P0216

Injection Timing Control System

Yes

P0219

Engine Overspeed Condition

P0220

APP Sensor 2 Circuit

P0221

APP Sensor 2 Circuit Performance

P0222

APP Sensor 2 Circuit Low Voltage

P0223

APP Sensor 2 Circuit High Voltage

P0225

APP Sensor 3 Circuit

P0226

APP Sensor 3 Circuit Performance

P0227

APP Sensor 3 Circuit Low Voltage

P0228

APP Sensor 3 Circuit High Voltage

P0231

Lift Pump Secondary Circuit Low Voltage

Yes

P0236

TC Boost System

Yes

P0237

TC Boost Sensor Circuit Low Voltage

Yes

P0238

TC Boost Sensor Circuit High Voltage

Yes

P0251

Injection Pump Cam System

Yes

P0263

Cylinder Balance System Fault

P0266

Cylinder Balance System Fault

P0269

Cylinder Balance System Fault

P0272

Cylinder Balance System Fault

P0275

Cylinder Balance System Fault

P0278

Cylinder Balance System Fault

P0281

Cylinder Balance System Fault

PCM/Tech 1 Scan Tool

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P0284

Cylinder Balance System Fault

P0335

CKP Sensor Circuit Performance

Yes

P0370

Timing Reference High Resolution

Yes

P0380

Glow Plug Circuit Performance

Yes

P0501

Vehicle Speed Sensor Circuit

P0567

Cruise Resume Circuit

P0568

Cruise Set Circuit

P0571

Cruise Brake Switch Circuit

P0601

PCM Memory

P0602

PCM Not Programmed

P0606

PCM Internal Communication Interrupted

Yes

P1125

APP System

P1214

Injection Pump Timing Offset

Yes

P1216

Fuel Solenoid Response Time Too Short

P1217

Fuel Solenoid Response Time Too Long

P1218

Injection Pump Calibration Circuit

Yes

P1621

EEPROM Write

Yes

P1627

A/D Performance

Yes

P1635

5 Volt Reference Low

P1641

Malfunction Indicator Lamp (MIL) Control Circuit

P1643

Write to Start Lamp Control Circuit

P1654

Service Throttle Soon (STS) Lamp Control Circuit

P1656

Wastegate Solenoid Control Circuit

Yes

Diagnostic Trouble Code (DTC) Identification (Contd)

DTC

Description

Type

Illuminate MIL

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