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Ask Chad Farhat Your Own Question
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: Pontiac
Satisfied Customers: 3839
Experience:  Owner at Carolina Auto Service & Sales , 20 years Experience in Foreign & Domestic vehicles
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Service engine soon light. coes are p1189 and po442. The

Customer Question

service engine soon light. coes are p1189 and po442
JA: Do you have the trouble code? Do you have a code reader or scan tool?
Customer: yes the codes are above
JA: Great. If you share the code with me, I'll pass it along to the Pontiac Mechanic. He'll be able to diagnose your issue much faster with a code. What is the model/year of your Pontiac?
Customer: 2003 pontiac montana p1189 and po442
JA: Are you fixing your Montana yourself? What have you tried so far?
Customer: nothing becuase it just happened and I dont know if IM fixing it myself becauise dont know what the codes realate to
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 8 months ago.
Category: Pontiac
Expert:  Chad Farhat replied 8 months ago.

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Expert:  Chad Farhat replied 8 months ago.

Hey how are you

SYSTEM DESCRIPTION This DTC tests the evaporative emission (EVAP) system for a small leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the control module turns the EVAP canister purge valve ON and the EVAP vent valve ON. This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the control module turns the EVAP canister purge valve OFF, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum decay. If the control module detects a leak larger than a calibrated amount, this DTC sets.

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The table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent valves.

- DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121, P1122 are not set.
- The ignition voltage is between 10-18 volts.
- The barometric pressure (BARO) is more than 75 kPa.
- The fuel level is between 15-80 percent.
- The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
- The intake air temperature (IAT) is between 4-30°C (39-86°F).
- The start up ECT and IAT are within 9°C (16°F) of each other.
- The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

The EVAP system can achieve vacuum, but a vacuum decay is detected during the diagnostic test.

- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

- To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light.
- To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT.
- For intermittent conditions refer to Intermittent Conditions. See: Computers and Control Systems > Initial Inspection and Diagnostic Overview > Intermittent Conditions


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The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies that a failure condition is present.
4. Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
6. This step verifies that repairs are complete and that no other condition is present.

Expert:  Chad Farhat replied 8 months ago.

2003 Pontiac Truck Montana V6-3.4L VIN E

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DTC P1189 CIRCUIT DESCRIPTION The engine oil pressure switch is a normally closed switch that opens with the proper oil pressure. With the ignition switch turned ON and the engine not running, the PCM should detect a low signal voltage input. With the engine running, the pressure switch opens, and the PCM should detect a high signal voltage input. The PCM tests the state of the engine oil pressure circuit with the ignition switch turned ON, and the engine turned OFF. If the PCM detects a high voltage input on the engine oil pressure signal circuit, DTC P1189 will set. CONDITIONS FOR RUNNING THE DTC - The ignition is ON, with the engine OFF. - DTC codes P0117, P0118, P1111, and P1114 are not set. CONDITIONS FOR SETTING THE DTC - The PCM detects that the engine oil pressure switch signal circuit is high. - The above condition is present for greater than 10 seconds. ACTION TAKEN WHEN THE DTC SETS - The PCM will not illuminate the malfunction indicator lamp (MIL). - The PCM will store conditions which were present when the DTC set as Fail Records data only. The information will not be stored as Freeze Frame data. CONDITIONS FOR CLEARING THE MIL/DTC - A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. - The PCM receives the clear code command from the scan tool. TEST

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Expert:  Chad Farhat replied 8 months ago.

Please let me know if you need anything else on it, just reply back and we will continue

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Chad Farhat
ASE Certified Technician

Customer: replied 8 months ago.
I dont even know what that all means. in laymans terms please?
Customer: replied 8 months ago.
I cant do that sorry. thanks for your time