09 Cobalt SS P1089 Code
 

Has anyone else had this code on their car? I got it recently. Car is in reduced power mode. The code p1089 is fuel rail pressure circuit low. I replaced the fuel pressure sensor on the rail and it worked for about a week now I am back to the same issue. Anyone have any thoughts here?

Check the wiring to the sensor

Alright guys I still need help with this issue. Car runs ok when cold for about 5 miles then fuel pressure only shows dashes on rpd and goes into limp mode or reduced power mode. I have check wiring to map, tmap and cleaned them both. Replaced the hpfp and checked its wiring. Replaced the fuel rail pressure sensor and checked its wiring it also looks good. I dont know what else to do. Very frustrating. The codes I get are P0642, P0192, P0193, and P0189. Anyone have any ideas or have this happen to them that can help me?

P0642 is pretty rare and pretty telling to me. 5-Volt Reference 1 Low Voltage

Also having P0192 and P0193 at the same time is strange.

To me it seems like you have a power issue going to the sensor. Not getting 5V properly.

I would guess you need to pull the harness apart and look for issues. Wiring issues suck.

Which sensor do you believe it would be the fuel pressure sensor or the hpfp wiring? The only thing with the fuel pressure sensor I can only follow it for about 2 inches before it goes behind the intake manifold. I followed the hpfp wiring and I didn't see an issue there at all.

Anyone else have any ideas on this?

I just found this as well. Do you have Stage 1 sensors installed? This is a Service Bulletin for the HHR SS.

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
A technician may comment that DTC's (P0642 / P0193) may set after installing the Performance Parts accessory upgrade Stage I Turbo kit. They may report the vehicles will crank but not start and they have rechecked their installation with no problems found.

Recommendation/Instructions:
Due to differences in the new sensors and wiring harness colors between vehicle models some confusion may occur when installing the new TMAP sensors. The following may help.

The technician may mistake the intake manifold TMAP sensor with the Charge air pipe TMAP sensor which is located on the charge air pipe from the turbocharger. This may lead to the technician rewiring the sensor for the wrong location.
The technician may be confused at steps #4 and #10 where they are to rewire the new sensors. Due to production differences the wire colors do not correspond to those found on the vehicle. In addition eSI documents for the 2008-09 HHR may not be correct for these circuits. (eSI change request has been submitted) This may cause the technician to install the pigtail incorrectly. To remedy this concern match the production terminal to the provided terminal. (Pin to pin) Follow these charts below from the installation instructions for reference. (Production wire colors omitted)

INTAKE MANIFOLD TMAP SENSOR WIRING
Production Terminal Location
New Wire Color
New Terminal Location

A/1 White 3

B/2 White 1

C/3 White 4


Pin # 2 is not used; cover and tape back the white wire.

CHARGE AIR PIPE TMAP SENSOR WIRING
Production Terminal Location
New Wire Color New Terminal Location

A White 1

B White 2

C White 3

D White 4


Note: When installing the TMAP sensor on the Charge air pipe the technician may notice interference between the pipe and the new sensor. This has been addressed in PIC5062, which details removing a boss from the sensor to allow proper alignment.

No I don't which is weird. Car is stock besides K&N intake and zzp intercooler.

Bump anyone else have any ideas? I'm totally unsure on what to do next