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.
Inspect for the following conditions:
- Any unmetered air-Any unmetered air that enters the engine downstream of the MAF sensor may cause this DTC to set.
- A sluggish or unresponsive MAF sensor-A short between the signal circuit of the MAF sensor and the signal circuit of the intake air temperature (IAT) sensor. This will cause the MAF sensor to have a very limited output voltage range.
- A malfunctioning MAF sensor can cause excessive engine emissions.
- An open on the 5-volt reference circuit of the barometric pressure (BARO) sensor may cause this DTC to set.
- A short to ground on the signal circuit of the BARO sensor may cause this DTC to set.
- The signal circuit of the BARO sensor shorted to 5 volts may cause this DTC to set.
- An open signal circuit of the BARO sensor may cause this DTC to set.
- The MAF display should increase from 42-50 g/s at idle to 420 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 vehicle condition is intermittent, refer to Intermittent Conditions .
DTC P0101
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls 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 |
|
- | Go to Diagnostic Trouble Code (DTC) List | Go to Step 3 |
| 3 |
|
- | Go to Step 4 | Go to Diagnostic Aids |
| 4 | Inspect the fuse in the ignition 1 voltage circuit of the mass air flow (MAF) sensor. Is the fuse open? |
- | Go to Step 17 | Go to Step 5 |
| 5 |
|
- | Go to Step 26 | Go to Step 6 |
| 6 |
|
4 kPa | Go to Step 7 | Go to DTC P2227 (Federal RPO FE9, NG1) or DTC P2227 (California RPO YF5, NE1, and VCL) |
| 7 |
|
- | Go to Step 21 | Go to Step 8 |
| 8 | Observe the MAF Sensor parameter with a scan tool. Is the MAF Sensor parameter less than the specified value? |
16 g/s | Go to Step 11 | Go to Step 9 |
| 9 | Observe the MAF Sensor parameter with a scan tool. Is the MAF Sensor parameter more than the specified value? |
445 g/s | Go to Step 10 | Go to Step 11 |
| 10 | Disconnect the harness connector of the MAF sensor. Is the MAF Sensor parameter more than the specified value? |
445 g/s | Go to Step 15 | Go to Step 11 |
| 11 |
|
- | Go to Step 12 | Go to Step 17 |
| 12 |
IMPORTANT:
All electrical components and accessories must be turned OFF.
|
5 ohm | Go to Step 13 | Go to Step 18 |
| 13 |
|
445 g/s | Go to Step 22 | Go to Step 14 |
| 14 |
|
- | Go to Step 26 | Go to Step 16 |
| 15 |
IMPORTANT:
Disconnecting the ECM connectors may eliminate the short to voltage if the signal circuit is shorted to another ECM circuit.
|
0 V | Go to Step 16 | Go to Step 19 |
| 16 | Test for continuity at the harness connector of the ECM from the signal circuit of the MAF sensor to all other circuits at both ECM connectors with a DMM. Refer to Circuit Testing
in Wiring Systems. Does the DMM indicate continuity between any other circuit? |
- | Go to Step 20 | Go to Step 23 |
| 17 |
|
- | Go to Step 26 | Go to Step 24 |
| 18 | Repair the high resistance or an open in the low reference circuit of the MAF sensor. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 26 | Go to Step 23 |
| 19 | Repair the short to voltage in the signal circuit of the MAF sensor. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 26 | - |
| 20 | Repair the circuits that are shorted together. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 26 | - |
| 21 | Repair the harness or the connections as necessary. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 26 | - |
| 22 | Inspect for poor connections at the harness connector of the MAF sensor. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 26 | Go to Step 24 |
| 23 | Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 26 | Go to Step 25 |
| 24 | 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 26 | - |
| 25 | Replace the ECM. Refer to Engine Control Module (ECM) Replacement
. Did you complete the Replacement? |
- | Go to Step 26 | - |
| 26 |
|
- | Go to Step 2 | Go to Step 27 |
| 27 | 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 |