Hummer H2. Manual - part 2500

8

Measure the resistance from terminal E to ground, and 
from terminal U to ground. 
Do both readings measure greater than the specified 
value?

250 K 

ohm

Go to 

Intermittent 

Conditions in 

Engine Controls - 

6.0L (LQ4)

Go to Step 10

9

1. Disconnect the AT wiring harness assembly 

from the TCC PWM solenoid valve.  

2. Measure the resistance of the TCC PWM 

solenoid valve.  

Does the resistance measure within the specified 
range?

10-15 

ohm

Go to Step 17

Go to Step 18

10

1. Disconnect the AT wiring harness assembly 

from the TCC PWM solenoid valve.  

2. Measure the resistance from each of the 

component terminals to ground.  

Do both readings measure greater than the specified 
value?

250 K 

ohm

Go to Step 17

Go to Step 18

11 Test the Ignition 0 voltage circuit of the TCC PWM 

solenoid valve for a short to ground between the fuse 
block and the AT inline 20-way connector.Refer to 
Testing for Short to Ground and extxref 
document="029_body-21" filetype="sgml" 
extrefid="i162420">Wiring Repairs in Wiring 
Systems.Did you find and correct the condition?

IMPORTANT:

The condition that affects this circuit may exist in 
other connecting branches of the circuit. Refer to 
Power Distribution Schematics in Wiring Systems 
for complete circuit distribution.

-

Go to Step 20

Go to Step 12

12

Test the Ignition 1 voltage circuit of the TCC PWM 
solenoid valve for a short to ground between the AT 
inline 20-way connector and the TCC PWM solenoid 
valve.Refer to Testing for Short to Ground in 
Wiring Systems.Did you find a short to ground 
condition?

IMPORTANT:

The condition that affects this circuit may exist in 
other connecting branches of the circuit. Refer to 
Power Distribution Schematics in Wiring Systems 
for complete circuit distribution.

-

Go to Step 17

Go to Step 13

1. Test each solenoid for a short to ground.  

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2

 

13

2. Replace the faulty solenoid as necessary.  

Did you complete the replacement?

-

Go to Step 20

-

14

Test the Ignition 0 voltage circuit of the TCC PWM 
solenoid valve for an open.Refer to Testing for 
Continuity and extxref document="029_body-21" 
filetype="sgml" extrefid="i162420">Wiring Repairs 
in Wiring Systems.Did you find and correct the 
condition?

IMPORTANT:

The condition that affects this circuit may exist in 
other connecting branches of the circuit. Refer to 
Power Distribution Schematics in Wiring Systems 
for complete circuit distribution.

-

Go to Step 20

-

15

Test the control circuit of the TCC PWM solenoid 
valve for a short to ground between the PCM 
connector C2 and the AT inline 20-way connector. 
Refer to Testing for Short to Ground and extxref 
document="029_body-21" filetype="sgml" 
extrefid="i162420">Wiring Repairs in Wiring 
Systems. 
Did you find and correct the condition?

-

Go to Step 20

Go to Step 19

16

Test the control circuit of the TCC PWM solenoid 
valve for an open or short to voltage between the 
PCM connector C2 and the AT inline 20-way 
connector. 
Refer to Circuit Testing and extxref 
document="029_body-21" filetype="sgml" 
extrefid="i162420"> Wiring Repairs in Wiring 
Systems. 
Did you find and correct the condition?

-

Go to Step 20

Go to Step 19

17

Replace the AT wiring harness assembly. 
Refer to Valve Body and Pressure Switch 
Replacement . 
Did you complete the replacement?

-

Go to Step 20

-

18

Replace the TCC PWM solenoid valve. 
Refer to Valve Body and Pressure Switch 
Replacement . 
Did you complete the replacement?

-

Go to Step 20

-

19

Replace the PCM. 
Refer to Powertrain Control Module (PCM) 
Replacement in Engine Controls - 6.0L (LQ4). 
Did you complete the replacement?

-

Go to Step 20

-

Perform the following procedure in order to verify the 
repair: 

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2

 

DTC P2771 

20

1. Select DTC.  

2. Select Clear Info.  

3. Drive the vehicle in D4 with the TCC On. 

Ensure that the following conditions are met: 

z

The PCM commands the TCC PWM 
solenoid valve ON, and the voltage 
feedback drops to zero.  

z

The PCM commands the TCC PWM 
solenoid valve OFF, and the voltage 
feedback increases to B+.  

z

All conditions are met for 5 seconds.  

4. Select Specific DTC.  

5. Enter DTC P2761.  

 
Has the test run and passed?

-

Go to Step 21

Go to Step 2

21

With the scan tool, observe the stored information, 
capture info, and DTC Info. 
Does the scan tool display any DTCs that you have 
not diagnosed?

-

Go to Diagnostic 

Trouble Code 

(DTC) List in 

Engine Controls - 

6.0L (LQ4)

System OK

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2

 

Fig. 24: Four Wheel Drive (4WD) Low Circuit Diagram 
Courtesy of GENERAL MOTORS CORP. 

Circuit Description 

The four wheel drive (4WD) low circuit consists of the powertrain control module (PCM), a transfer case 
control module and the circuit wiring. The transfer case control module controls the 4WD low signal on the low 
signal circuit. When the operator selects 4WD low, the transfer case control module grounds the signal circuit, 
and the 4WD low signal voltage on the circuit changes from ignition voltage to zero volts. The PCM then 
compensates for transfer case gear reduction in the transmission output shaft speed (OSS) sensor signal. The 
PCM uses the transmission OSS sensor signal to adjust shift points, line pressure and torque converter clutch 
(TCC) scheduling. 

When the PCM detects a continuous open, short to ground or short to power in the 4WD low circuit, then DTC 
P2771 sets. DTC P2771 is a type B DTC. 

Conditions for Running the DTC 

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E Diagnosis (DTC P0218 To DTC P2771) - Hummer H2