Hummer H1 (2002+). Manual - part 277

 

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PCM/Tech 1 Scan Tool 38.3

 

 

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05745159

 

Test Description

 

Number(s) below refer to step numbers on the diagnostic table.

2. An ECT failure could cause a DTC P0126 to set, so 

correct any ECT DTC that are set.

6. If it is obvious that the engine is not reaching full 

operating temperature, for example the radiator 
hoses never get vary warm, or there is a complaint 
of little or no heat from the heater, this step could 
be skipped.

 

DTC 

 

P

 

0126 Engine Coolant Temperature (ECT) Insufficient for Stable Operation

 

Step

Action

Value(s)

Yes

No

 

1

 

Important: 

 

Before clearing any DTCs, use the scan tool 

option “Capture Info” to save freeze frame and failure 
records for reference, as the scan tool loses data when 
using the “Clear Info” function.

–––

Go to step 2.

Go to A Powertrain On 

Board Diagnostic 

(OBD) Systems Check

2

Are any engine coolant temperature DTCs set?

–––

Go to the applicable 

DTC table.

Go to step 3.

3

a.

Connect the scan tool.

b.

Turn the ignition to the “RUN” position leaving 
the engine off.

c.

Disconnect the ECT sensor.

Does the scan tool indicate the ECT sensor is at a tempera-
ture colder than the specified value?

-35˚C (-31˚F)

Go to step 4

Go to the diagnostic 

chart for P0117 Engine 

Coolant Temperature 
(ECT) Sensor Circuit 

Low Voltage.

4

Using a jumper wire, jumper the terminals at the ECT sen-
sor harness connector together.
Does the scan tool indicate the ECT sensor is at a tempera-
ture colder than the specified value?

150˚C (302˚F)

Go to step 5

Go to the diagnostic 

chart for DTC P0117 

Engine Coolant Tem-

perature (ECT) sensor 

Circuit Low Voltage.

5

a.

Reconnect the ECT sensor.

b.

Start and idle the engine.

c.

With the engine idling, observe the ECT sensor 
display on the “Engine 1 Data List” option on the 
scan tool.

 

Important:

 

 Allow time for the engine to warm up if it has 

not already reached the specified temperature. 7 minutes is 
the maximum amount of time it should take to reach this 
temperature from a cold start. Less time should be neces-
sary if the engine is already warm. 
Does the scan tool indicate the engine coolant temperature 
has reached the specified value?

60˚C (140˚F)

System must be 

rechecked on a cold 
start. Refer to Diag-

nostic Aids.

Go to step 6.

6

Using a Digital Multi Meter measure the resistance of the 
DCT sensor. Refer to Temperature vs. Resistance.
Is the ECT resistance close to the value indicated in the 
Temperature vs. Resistance Table

___

Go to step 7.

Go to step 8.

7

For an engine cooling system problem, check for the fol-
lowing conditions:

• Thermostat operation 

• Coolant level

• Coolant to water ratio

• Cooling fan operation etc.

Refer to 

 

Engine Cooling.

 

Is the action complete?

___

Go to step 9.

___

8

Replace the ECT sensor. Refer to 

 

ECT Sensor Replace-

ment.

 

Is the action Complete?

___

Go to step 9.

___

 

3-1-01

 

38.4

PCM/Tech 1 Scan Tool

 

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9

a.

Using the Scan tool, clear the DTCs.

b.

Start the engine and idle at normal operating tem-
perature.

c.

Select “DTC Specifications”, then enter the num-
ber which was set.

d.

Operate the vehicle, within the conditions for set-
ting this DTC, until the scan tool indicates the di-
agnostic has run.

Does the scan tool indicate the diagnostics passed?

___

Go to step 10.

Go to step 2.

10

Does the scan tool display any additional undiagnosed 
DTCs?

___

Go to the applicable 

DTC table.

System is OK.

 

DTC 

 

P

 

0126 Engine Coolant Temperature (ECT) Insufficient for Stable Operation

 

Step

Action

Value(s)

Yes

No

 

3-1-01

 

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PCM/Tech 1 Scan Tool 39

 

 

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05745159

 

DTC P0182 Fuel Temperature Sensor Circuit 
Low Voltage

 

Circuit Description

 

The fuel temperature sensor is a thermistor that controls signal
voltage to the PCM. When the fuel is cold, the sensor resis-
tance is high, therefore the PCM will see high signal voltage.
As fuel warms, sensor resistance becomes less and voltage
drops. The fuel temperature sensor is integrated with the opti-
cal sensor. This is a type B DTC.

 

Conditions for Setting the DTC

 

• Fuel temperature greater than 102°C (215°F).

• Conditions met for 2 seconds.

 

Action Taken When the DTC Sets

 

Poor idle quality during hot conditions.

 

Conditions for Clearing the MIL/DTC

 

• The PCM will turn the MIL off after three consecutive

trips without a fault condition.

• A History DTC will clear when forty consecutive

warm-up cycles that the diagnostic does not fail (coolant
temperature has risen 5°C (40°F) from start up coolant
temperature and engine coolant temperature exceeds
71°C (160°F) that same ignition cycle).

• Use of a Scan Tool.

 

Diagnostic Aids

 

A scan tool reads fuel temperature in degrees centigrade. After
engine is started, the fuel temperature should rise steadily.

 

Test Description

 

Number(s) below refer to the number(s) on the diagnostic table.

1. This step determines if DTC P0182 is a hard failure or an in-

termittent condition.

3. This step will determine if signal circuit is shorted to

ground.

A

E

B

F

D

C

5 VOLT
REFERENCE

OPTICAL/ FUEL
TEMP SENSOR

PUMP CAM

SENSOR

SIGNAL

HIGH

RESOLUTION

SIGNAL

SENSOR

GROUND

M

D

A

B

C

C5

C3

B8

C1

C12

C2

375 GY

442 BR

703 OR

156 PK

225 YL

C27-D14

C29-A4

C29-A2

C27-D9

C27-C8

FUEL TEMP
SIGNAL

SENSOR
GROUND

HIGH
RES
SIGNAL

CAM
SENSOR
SIGNAL

5 VOLT
REFERENCE

INJECTION TIMING

STEPPEN MOTOR (ITS)

A3

A2

A6

A7

709 RD

708 TN

710 OR

71

1 YL

C29

A8

A9

A10

A7

ITS
HI

ITS
LO

ITS
LO

ITS
HI

POWERTRAIN

CONTROL

MODULE

9-S12-070

Powertrain
Control
Module

(PCM)

 

3-1-01

44

PCM/Tech 1 Scan Tool

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DTC P0215 - Engine Shutoff Solenoid Circuit Malfunction

Step

Action

Value(s)

Yes

No

1

Important:

 Before clearing DTC(s) use the scan tool “Capture Info” to

record Freeze Frame and Failure Record for reference, as data will be lost
when “Clear Info” function is used.

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

—

Go to Step 2.

Go to OBD 

System Check.

2

1. Ignition “ON”, engine “OFF”.
2. Using scan tool, command ESO “ON” and “OFF”.

Does ESO respond to scan tool commands?

—

Go to Step 4. Go to Step 3.

3

1. Ignition “OFF”.
2. Disconnect the PCM electrical connector.

3. Ignition “ON”, engine “OFF”.

4. With a test light connected to chassis ground, probe ESO control circuit

at PCM harness connector.

Is test light “ON”.

—

Go to Step 5.

Go to Step 6.

4

DTC is intermittent. If no additional DTCs are stored, refer to “Diagnostic 
Aids”. If additional DTCs are stored refer those table(s).

—

—

—

5

Check the ESO control circuit for a poor connection at the PCM and replace 
terminal if necessary.
Did the terminal require replacement?

—

Go to Step 8.

Go to Step 7.

6

1. Check the ESO control circuit for:

• an open

• faulty bulb

• faulty fuse

2. If the ESO control circuit was faulty, repair it as necessary.

Was repair performed?

—

Go to Step 8.

—

7

Replace the faulty PCM. Notice: If the PCM is faulty, the new PCM must 
be programmed. Go to PCM replacement and programming procedures.
Is the action complete?

—

Go to Step 8.

—

8

1. Using the Scan Tool, select “DTC”, “Clear Info”.
2. Start engine and idle at normal operating temperature.

3. Select “DTC”, “Specific”, then enter the DTC number which was set.

4. Operate vehicle within the conditions for setting this DTC as specified in

the supporting text.

Does the Scan Tool indicate that this diagnostic Ran and Passed?

—

Go to Step 10.

Go to Step 2.

9

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

—

Go to the 

applicable 

DTC table

Go to Step 2.