Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2006COBALT SS, 4D SEDAN, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 387 (ENGINE CONTROL SYSTEM - 3.9L - DTC P0442 TO DTC P2A01)DTC P0641 OR P0651CIRCUIT/SYSTEM TESTING
2006 Chevrolet Cobalt SS, 4D Sedan, Standard
Circuit/System Testing
2006 Chevrolet Cobalt SS, 4D Sedan, StandardSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2006 Chevrolet Monte Carlo and 2006 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
P0641
- Disconnect the MAP sensor electrical connector.
- With the ignition ON and the engine OFF, measure for 4.8-5.2 volts from the 5-volt reference circuit of the MAP sensor to ground with a DMM.
- If the voltage is more than 5.2 volts, test for a short to voltage on the 5-volt reference circuits of all the sensors connected to the 5-volt reference A bus, a short to voltage on the FTP sensor signal circuit, or a faulty control module.
- If the voltage is less than 4.8 volts, test for a short to ground on the 5-volt reference circuits of all the sensors connected to the 5-volt reference A bus, or a faulty control module.
- Measure the voltage from the 5-volt reference circuit of the MAP sensor to ground. Monitor the DMM while disconnecting all other sensors connected to the 5-volt reference A bus, one at a time.
- If the voltage returns to 4.8-5.2 volts when a sensor is disconnected, replace the applicable sensor.
- Reconnect all sensors except the EOP sensor.
- Measure for 4.8-5.2 volts from the 5-volt reference circuit of the EOP sensor to ground with a DMM.
- If the voltage is not within 4.8-5.2 volts, test for a short to voltage on the MAP sensor signal circuit or a faulty MAP sensor.
P0651
- Disconnect the throttle body electrical connector.
- With the ignition ON and the engine OFF, measure for 4.8-5.2 volts from the 5-volt reference circuit to ground with a DMM.
- If the voltage is more than 5.2 volts, test for a short to voltage on the 5-volt reference circuits of APP sensor 1 and TP sensor 1 and 2 or for a faulty control module.
- If the voltage is less than 4.8 volts, test for a short to ground on the 5-volt reference circuits of APP sensor 1 and TP sensor 1 and 2, or a faulty control module.
- Continue to measure the voltage from the 5-volt reference circuit of the throttle body electrical connector to ground. Monitor the DMM while disconnecting APP sensor 1.
- If the voltage returns to 4.8-5.2 volts when APP sensor 1 is disconnected, replace the APP sensor.
- Connect the throttle body electrical connector.
- With the ignition ON and the engine OFF, measure for 4.8-5.2 volts from the 5-volt reference circuit to ground with a DMM.
- If the voltage is not within 4.8-5.2 volts, replace the throttle body assembly.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.