Diagnostic Aids
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- The MAF Sensor parameter should increase from 24-50 g/s at idle to 320 g/s or more at the 2-3 shift during a wide-open throttle (WOT) acceleration. If not, inspect for a restriction in the induction system or the exhaust system.
- If the condition is intermittent, refer to Intermittent Conditions and Inducing Intermittent Fault Conditions in Wiring Systems.
DTC P0102
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views |
||||
| 1 | Did you perform the Diagnostic System Check - Engine Controls? | - | Go to Step 2 | Go to Diagnostic System Check - Engine Controls |
| 2 | Start the engine. Does the engine have fuel knock/combustion noise? |
- | Go to Step 5 | Go to Step 3 |
| 3 |
|
0.42 V | Go to Step 6 | Go to Step 4 |
| 4 |
|
- | Go to Step 6 | Go to Diagnostic Aids |
| 5 | With the engine running, disconnect the mass air flow (MAF)/intake air temperature (IAT) sensor. Does the engine have fuel knock/combustion noise? |
- | Go to Step 12 | Go to Step 15 |
| 6 |
|
- | Go to Step 19 | Go to Step 7 |
| 7 |
|
- | Go to Step 22 | Go to Step 8 |
| 8 | Inspect the fuse in the ignition 1 voltage circuit of the MAF sensor. Is the fuse open? |
- | Go to Step 11 | Go to Step 9 |
| 9 |
|
B+ | Go to Step 10 | Go to Step 17 |
| 10 |
|
445 g/s | Go to Step 15 | Go to Step 13 |
| 11 |
IMPORTANT:
The ignition 1 voltage circuit of the MAF sensor is spliced to other components of the vehicle. Test the MAF sensor ignition 1 voltage circuit for the following conditions:
|
- | Go to Step 22 | - |
| 12 |
|
- | Go to Step 22 | Go to Step 16 |
| 13 |
|
- | Go to Step 22 | Go to Step 14 |
| 14 | Measure the resistance from the signal circuit of the MAF sensor to all other circuits at all ECM connectors with a DMM. Refer to Circuit Testing
in Wiring Systems. Is the resistance less than the specified value? |
infinity ohm | Go to Step 18 | Go to Step 16 |
| 15 | Test for shorted terminals and for an intermittent and for a poor connection at the MAF/IAT sensor. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
and Repairing Connector Terminals
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 20 |
| 16 | Test for shorted terminals and for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
and Repairing Connector Terminals
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 21 |
| 17 | Repair the high resistance or the open in the MAF sensor ignition 1 voltage circuit. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 22 | - |
| 18 | Repair the circuits that are shorted together. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 22 | - |
| 19 | Repair the harness or the connections as necessary. Refer to Connector Repairs
and Repairing Connector Terminals
and Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 22 | - |
| 20 | Replace the MAF/IAT sensor. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement
. Did you complete the replacement? |
- | Go to Step 22 | - |
| 21 | Replace the ECM. Refer to Engine Control Module (ECM) Replacement
. Did you complete the replacement? |
- | Go to Step 22 | - |
| 22 |
|
- | Go to Step 2 | Go to Step 23 |
| 23 | With a scan tool observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? |
- | Go to Diagnostic Trouble Code (DTC) List | System OK |