GMC Terrain, Equinox, and SRX Forum banner
1 - 15 of 15 Posts

·
Registered
Joined
·
95 Posts
Discussion Starter · #1 ·
Hi, I had an engine MIL about 12,000 miles ago and it just disappeared all by itself. Just last weekend, it appeared again and disappeared after a few starts and drives. Also twice the Stabilitrac with reduce power appeared. I hook up My OBDlink MX with OBDlink app and it shows the code P0697 5 V reference permanent. The two phasers were replaced about 9 months ago so I ordered the throttle body and just installed it. Other than that the engine runs smoothly with only 1 or two misfires for many cycles that the scan has shown. I clear the code so there is no code on the dash as of now. All the parts replaced are AC Delco from Rockauto. Is there any thing else I should look out for if the light returns? The Nox is 2011 with the famous 2.4L now at 120,000 miles.
 

·
Registered
Joined
·
95 Posts
Discussion Starter · #2 ·
The reduce power and service stabilitrack just appears again today. I measure the battery voltage and it is 12.63 V. The car still idles smooth. I just drive it on city road not above 40 mph so I don't know how it will run at high way speed. Is there anything that I should look for?
 

·
Registered
2011 Equinox 1LT V6 3.0L FWD 174.6k miles
Joined
·
4,510 Posts
My 2011 Shop Manual says P0697 (for the 2.4L engine) is the 5V reference #3 circuit that provides 5V to the following sensors:

1.) MAP sensor (Manifold Absolute Pressure)
2.) Accelerator pedal Position Sensor 2

Testing:
1.) Ignition OFF, Disconnect the harness connectors of both sensors
2.) Ignition ON, test for 4.8-5.2V between one of the affected 5V reference circuits and ground

IF voltage is less, test for short to ground on the 5V reference circuit for each affected component. If all circuits test normal, replace the ECM

IF the voltage is greater, test for short to voltage on the 5V reference circuit for each affected component. if all circuits test normal, replace the ECM

NOTE: a short to voltage on the signal circuit of certain components may also cause this DTC

3.) Connect each component associated with the affected 5V reference circuit one at a time while monitoring the appropriate scan tool 5V Reference Circuit Status parameter. The parameter should continue to display OK. If the parameter displays Malfunction when a component is connected, test the signal circuit of that component for a short to voltage. If it tests normal, replace the component. (You probably cannot see the status parameter with your scanner, correct? This is probably a dealer, or high-end scanner capability).

=============
Since you've already replaced the Throttle Body (with new OEM sensors, I'm assuming ??), and you're still getting the "Reduced Engine Power" message, I would start with the Accelerator Pedal Sensor 2, which also factors into the Throttle Actuator Control System (TAC), which is one of four inputs to the ECM which could cause it to post that message (the others being Ignition Voltage, Cruise Control Switch, and Throttle Body sensors).

But the 5V #3 Reference Circuit can be found on the MAP plug. Looking at the plug with the clip at the top, it's the left corner pin (GY), On the Accelerator Pedal Sensor it's the 4th (of 6 pins) from the left. On this plug, the leftmost pin is actually the 5V #4 Reference Circuit because the first 3 pins from the left are for sensor 1 and the 2nd 3 pins are for sensor 2.
 

·
Registered
Joined
·
95 Posts
Discussion Starter · #4 ·
Thank you for taking time to write a very detail instruction. At first, I was mistaken the MAF for MAP sensor. I managed to measure the MAF voltage. It is 4.92 V.
After I hooked the MAF back and started the vehicle, I heard the radiator fan running. It seems odd since it is the first start of the day. I shut it down and restart. The radiator fan does not run anymore. I then tried to remove the Accelerator connector without success. It is a bit hard to access and I just did not want to break the connector or wire bundle without further research on how to remove it. I broke a tab on the black bottom panel above the knee. I hooked up the OBD and saw another code P0113 Intake Air Temp along with P0697. I guess when I removed the MAF for voltage reading, the car must receive some erroneous value when it is not there. After some research and realize about the MAP and MAF,
I unplugged and measured the voltage of the MAP sensor. It is also 4.92 V. After putting the MAP plug back and hook up the OBD, both the P0697 and P0113 are gone. However, there is a new code P0107 for the MAP. Could it be because it was unplugged for checking the voltage? I clear the code and stop there. The wife needs the car for work tomorrow. I will buy and replace the MAP sensor tomorrow anyway since it is cheap. I attached both the reports scanned after MAF and MAP check.
 

Attachments

·
Registered
2011 Equinox 1LT V6 3.0L FWD 174.6k miles
Joined
·
4,510 Posts
After putting the MAP plug back and hook up the OBD, both the P0697 and P0113 are gone. However, there is a new code P0107 for the MAP. Could it be because it was unplugged?
Appears so. Shop Manual says P0107 appears if the ECM detects MAP sensor voltage less than 0.20V for more than 5 secs.

Similar situation for the P0113 on the Intake Air Temp Sensor (IAT), which is integrated into the MAF sensor.
 

·
Registered
Joined
·
95 Posts
Discussion Starter · #6 ·
Just to follow up, I bought the MAP sensor but did not have time to install yet. I drove the vehicle this morning and notice it is very smooth and the Instantaneous MPG is high and steady. I reset the MPG and it shows 34.5 MPG for a stretch of 10 miles on the highway (65 MPH). I went home and performed a scan. All the codes are gone now. I guess just the mere act of disconnecting and re-connecting the MAP and MAF connectors fixed the problem. I will change out the MAP sensor anyway this weekend.
 

Attachments

·
Registered
'16 Equinox LTZ AWD 3.6
Joined
·
1,564 Posts
I chased a bad MAP sensor on my Tahoe. It did not set any P codes either.
I lost 3-4 mpg highway, dropping to 16 mpg is not good.
My scan tool, AutoEnginuity PC based has a MAP test mode and I saw it go back and forth from pass to fail yet no P code would set. It also would not do the EVAP monitor OBD tests either after a battery disconnect.
After going through this the other tip off was the real time MPG would fluctuate from it's normal 90+ mpg on a long downhill coast down into the 50's and all over the place.
Just tossing this out incase it helps someone as I'm a gearhead and it had me scratching my head for a while and I'm a cheapskate and didn't want to throw the parts dart at a $60 MAP sensor for my 5.3 motor.
 

·
Registered
Joined
·
95 Posts
Discussion Starter · #8 ·
Update, the famous Reduce Engine Power appears this morning when starting the car. Everything was fine last night when I pulled into the garage. I checked with OBD-II scan and it is P0697 Reference voltage circuit C open. Luckily I had the state inspection last week (passed) so there is time to play with it. Any ideas will be appreciated.
 

·
Registered
Joined
·
3,081 Posts
Did you ever change the MAP sensor from your Reply #6 a few months ago?
 

·
Registered
Joined
·
95 Posts
Discussion Starter · #10 ·
Yes the MAP sensor was changed out a few months ago with an OEM AC Delco one. The car is still running fine after the code is cleared
 

·
Registered
Joined
·
95 Posts
Discussion Starter · #12 ·
My engine light pops up with the P0697 almost weekly now after clearing it. I just bought a Foxwell N716 to scan deeper into the car. I am still learing about scanning and the codes. There is a hidden U0100-71 code pulled. I attached all the scan here. Someone knowledgeable about the readings please point me how to fix this problem. Thanks
 

Attachments

·
Registered
Joined
·
3,081 Posts
DTC Code U0100-XXX is a short or open in the GMLAN serial data circuit.
 

·
Registered
Joined
·
95 Posts
Discussion Starter · #14 ·
Just to update. About a month ago, my car suddenly had the reduce power on the highway and the engine shut down. I was able to put it in neutral, coasted down to the feeder road and to a parking lot. While it was in neutral on the highway, I tried to restart the engine but no thing happened, just all the dash light lighted up. While in the parking lot, I removed the key then restarted the car. It started up with only a check engine light. I was able to go drive home that day. Brought to the dealer the next day. I told them I already replace the throttle body, MAF, MAP, solenoids. They diagnosed and said it is the accelerator. I told them to replace but at the end of the day they said the code is still there. Brought the car back the next day for further diagnosis, this time they said the ECM. They have to order it but no ETA available. It has been four week and now the reduce engine happens often and during driving. It only did it during starting before. It is dangerous to drive the car now.

While doing the search for the problem, I notice there are several sort of class action law suit about GM reduce power problem. I am thinking about joining one of them.
 

·
Registered
Joined
·
95 Posts
Discussion Starter · #15 ·
The ECM finally came in and replaced by the dealer. It has been 3 weeks of driving now and the Reduce Engine Power and Stabilitrack have not come back. To every one with the same problem, check you ECM. It can go bad and gives wrong reading/code
 
1 - 15 of 15 Posts
Top