Hummer H2. Manual — part 1684

(DTC) List

Go to Step 3

3

1. Turn ON the ignition, with the engine OFF.

2. Observe the throttle position (TP) sensor 1 and 2

Agree/Disagree parameter with a scan tool.

Does the scan tool TP sensor 1 and 2 Agree/Disagree
parameter indicate Disagree?

Go to Step 5

Go to Step 4

4

1. Remove the air inlet duct from the throttle body.

2. Disconnect the throttle body harness connector.

3. Connect the jumper wires between the TP sensor

terminals of the throttle body harness connector and
the corresponding TP sensor terminals of the throttle
body.

4. Observe the TP sensor 1 and 2 with a scan tool.

5. Slowly open the throttle blade to wide open throttle

(WOT) and back to the closed throttle position several
times by hand.

Does the TP sensor Agree/Disagree parameter change from
Agree to Disagree during the above test?

Go to Step 18

Go to Diagnostic

Aids

5

1. Disconnect the TP sensor harness connector.

2. Disconnect the throttle actuator control (TAC) module

harness connectors.

3. Test the TP sensor 1 5-volt reference circuit for

resistance with a DMM. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 6

6

Test for a short between the TP sensor 1 5-volt reference
circuit and all other TAC module circuits with a DMM.
Refer to Circuit Testing and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 7

7

Test the TP sensor 1 signal circuit for resistance with a
DMM. Refer to Circuit Testing and Wiring Repairs in
Wiring Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 8

8

Test for a short between the TP sensor 1 signal circuit and all
other TAC module circuits with a DMM. Refer to Circuit
Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 9

9

Test the TP sensor 1 low reference circuit for resistance with
a DMM. Refer to Circuit Testing and Wiring Repairs in

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0507 (TAC) To DTC U0107) - 4.8L, 5.3L, and 6.0L -

Hummer H2

Wiring Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 10

10

Test for a short between the TP sensor 1 low reference
circuit and all other TAC module circuits with a DMM.
Refer to Circuit Testing and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 11

11

Test the TP sensor 2 5-volt reference circuit for resistance
with a DMM. Refer to Circuit Testing and Wiring Repairs
in Wiring Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 12

12

Test for a short between the TP sensor 2 5-volt reference
circuit and all other TAC module circuits with a DMM.
Refer to Circuit Testing and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 13

13

Test the TP sensor 2 signal circuit for resistance with a
DMM. Refer to Circuit Testing and Wiring Repairs in
Wiring Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 14

14

Test for a short between the TP sensor 2 signal circuit and all
other TAC module circuits with a DMM. Refer to Circuit
Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 15

15

Test the TP sensor 2 low reference circuit for resistance with
a DMM. Refer to Circuit Testing and Wiring Repairs in
Wiring Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 16

16

Test for a short between the TP sensor 2 low reference
circuit and all other TAC module circuits with a DMM.
Refer to Circuit Testing and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 17

17

Inspect for an intermittent and for a poor connection at the
harness connector of the TAC module. Refer to Testing for
Intermittent Conditions and Poor Connections and
Repairing Connector Terminals in Wiring Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 18

18

Inspect for an intermittent and for a poor connection at the
harness connector of the throttle body. Refer to Testing for
Intermittent Conditions and Poor Connections and
Repairing Connector Terminals in Wiring Systems.
Did you find and correct the condition?

Go to Step 20

Go to Step 19

19

Replace the throttle body assembly. Refer to Throttle Body
Assembly Replacement .
Did you complete the replacement?

Go to Step 20

-

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0507 (TAC) To DTC U0107) - 4.8L, 5.3L, and 6.0L -

Hummer H2

DTC U0107

Circuit Description

The throttle actuator control (TAC) module and the powertrain control module (PCM) communicate via a
dedicated serial data circuit. This serial data circuit is separate from any other serial data circuit on the vehicle.
Accurate transmitting and receiving of serial data requires not only good circuit integrity, but also adequate
system voltage. This diagnostic test monitors the accuracy of the serial data transmitted between the TAC
module and the PCM. If the PCM detects a loss of data or invalid data, this DTC sets.

Conditions for Running the DTC

z

The ignition switch is in the Crank or Run position.

z

The ignition voltage is more than 5.23 volts.

Conditions for Setting the DTC

z

Invalid or missing serial data messages are detected for a predetermined amount of time.

z

The above condition is met for more than 1 second.

Action Taken When the DTC Sets

z

The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

z

The control module records the operating conditions at the time the diagnostic fails. The control module
stores this information in the Freeze Frame and/or the Failure Records.

z

The control module commands the TAC system to operate in the Reduced Engine Power mode.

z

A message center or an indicator displays Reduced Engine Power.

z

Under certain conditions the control module commands the engine OFF.

Conditions for Clearing the MIL/DTC

20

1. Clear the DTCs with a scan tool.

2. Turn OFF the ignition for 30 seconds.

3. Start the engine.

4. Operate the vehicle within the Conditions for Running

the DTC. You may also operate the vehicle within the
conditions that you observed from the Freeze
Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 21

21

Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?

Go to Diagnostic

Trouble Code

(DTC) List

System OK

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0507 (TAC) To DTC U0107) - 4.8L, 5.3L, and 6.0L -

Hummer H2

z

The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles
that the diagnostic runs and does not fail.

z

A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

z

A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other
emission related diagnostic.

z

Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

z

DTC U0107 sets if the battery voltage is low. If the customer's concern is slow cranking or no crank
because battery voltage is low, ignore DTC U0107. Clear any DTCs from memory that may have set
from the low battery voltage condition.

z

DTC U0107 sets when there is a short to B+ on the TAC module ground circuit. Inspect the fuses for the
circuits that are in the TAC module harness-i.e. cruise, brake. An inspection of the fuses may lead you to
the circuit that is shorted to the TAC module ground circuit.

z

DTC U0107 sets if the TAC module ignition feed circuit is shorted to a B+ supply circuit. The TAC
module stays powered-up when the ignition switch is turned OFF. When the ignition switch is turned ON,
the TAC module is powered-up before the PCM. DTC U0107 sets because no communication is detected
by the TAC module from the PCM. Inspect related circuits for being shorted to a B+ supply circuit.

z

Inspect the TAC module power and ground circuits and the TAC module/PCM serial data circuits for
intermittent connections.

z

Inspect the TAC module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs
may set without any circuit or component conditions found during diagnostic testing.

z

When the TAC module detects a problem within the TAC system, more than one TAC system related
DTC may set. This is due to the many redundant tests run continuously on this system. Locating and
repairing an individual condition may correct more than one DTC. Remember this if you review the
stored information in Capture Info.

z

For an intermittent condition, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

2: This step determines if the ignition relay is supplying a voltage to the ETC fuse.

5: Increasing the engine speed to 3,000 RPM aids in locating a shorted throttle actuator motor control
circuit. Depending on the polarity of the throttle actuator motor transistors, this DTC may not set with a
fault in the control circuits. The throttle actuator motor is a bi-directional DC motor. Raising the engine
speed changes the polarity of the transistors in the throttle actuator motor. This occurs because one set of
the transistors is low, 0 volts, and the other set is high, B+. Therefore, if one set of transistors is at a low
voltage and the corresponding circuit is shorted low, DTC P1518 will not set. When the polarity of the

IMPORTANT: Reprogramming the PCM may cause a communication error between the PCM

and the TAC. If the PCM detects a communication error, DTC U0107 sets. Clear
any DTCs from the memory that may have been set by Reprogramming.

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0507 (TAC) To DTC U0107) - 4.8L, 5.3L, and 6.0L -

Hummer H2